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  • 2001.
    Wolnievik, Niklas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för Industriell ekonomi, Elektro- och Maskinteknik.
    Projektering och beredning av ett distributionsnät i ett exploateringsområde2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete handlar om hur ett beredningsarbete går till från början till slut. Projektet omfattar ett eldistributionsnät till ett nytt bostadsområde med 33 villor, en förskola och en industrifastighet. Delar som effektförbrukning av bostäder, förskola och en industri har tagits fram utifrån deras huvudsäkring. Belastningsström och dimensionering av lågspänningskablar så som högspänningskablar har tagits fram för de olika delsträckorna som kabeln är förlagd. Spänningsfall på de olika delsträckorna för serviskablar och matarkablar samt spänningsfallen för abonnenterna blir behandlade i denna rapport, med mål att hålla dessa spänningsfall under 4 %. Utlösningsvillkor för de olika ledningssträckorna har kontrollerats för att hålla elnätet så säkert som möjligt. Den ekonomiska area har det tagits hänsyn till, för valet av de olika kablarna som har använts under arbetet. Arbetet behandlar också val av material från kabelskåp till säkringar. Ett flertal olika avtal har blivit behandlade, karttyper från schaktkarta till högspänningskarta har blivit framtagna. I ett projekt finns det ett flertal kostnader som är väsentliga för att få fram den slutgiltiga kostnaden. Vissa av dessa kostnader har blivit behandlade såsom: en P2-kalkyl är gjord och värderingsprotokoll för de olika markägarna har blivit framtagna. En presentation av de olika program som använts inom en beredning har tagits med, som kan hjälpa och underlätta arbetet som beredare. Resultatet av beredningen omfattar en ny 12/0,4 kV nätstation, nio stycken nya kabelskåp samt 155 meter 12 kV högspänningskabel och 4 087 meter 0,4 kV lågspänningskabel. Schaktsträckan kommer att vara 1 980 meter lång, där det schaktas fram till fastighetens gräns, där sedan fastighetsägarens ansvar för schaktningen tar vid. Nätstationen har placerats strategiskt, så att schaktningssträckorna minimeras och spänningsfallen hålls nere. Kabelskåpen har även de placerats strategiskt för att förse alla abonnenter med ström och med åtanke på spänningsfall så har servisledningarnas längd hållits nere. Kostnaden för projektet beräknas bli 2,1 miljoner kronor

    Fulltekst (pdf)
    fulltext
  • 2002.
    Wu, Ronghua
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Virtual Robotized NDT: Simulation in Robot Studio2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Human and machine cooperation has been developed for a long time to improve the productivity and because of advantages of the machine work, machine will play a more and more important role in the industrial production. To some extent, machine has already changed the world. This master thesis project was to use several robots build an automatic inspection line to inspect the wheel hub using the thermography with induction method. Three different methods are created in robot studio and the method with rotation tool was implemented as a demonstrator at PTC (production technology center).

    Compare the methods with each other and consider the limitations and productivity, the method with the rotation tool is the best choice for the company. The automation line includes several robots. In another words, the designed automation line can be considered to be several robot cells. Most sensors and calibration methods are set up due to the rules to build a robot cell. All signal analysis and processing are solved in the robot studio during the simulation process. Some needed robot cell components, equipment and different tools are used from the standard ABB robot studio library. Several special tools and equipment are designed and modelled in the NX and then converted to robot studio.

  • 2003.
    Wärmefjord, Kristina
    et al.
    Chalmers University of Technology, Dept. of Product and Production Development, SE-412 96 Gothenburg, Sweden.
    Söderberg, Rikard
    Chalmers University of Technology, Dept. of Product and Production Development, SE-412 96 Gothenburg, Sweden.
    Ericsson, Mikael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Appelgren, Anders
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Lundbäck, Andreas
    Luleå University of Technology, Dept. of Engineering Sciences and Mathematics, SE-971 87 Luleå, Sweden.
    Lööf, Johan
    GKN Aerospace,Engine Systems, SE-461 81 Trollhättan, Sweden .
    Lindkvist, Lars
    Chalmers University of Technology, Dept. of Product and Production Development, SE-412 96 Gothenburg, Sweden.
    Svensson, Hans-Olof
    GKN Aerospace,Engine Systems, SE-461 81 Trollhättan, Sweden .
    Welding of non-nominal geometries: physical tests2016Inngår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 43, s. 136-141Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The geometrical quality of a welded assembly is to some extent depending part positions before welding. Here, a design of experiment is set up in order to investigate this relation using physical tests in a controlled environment. Based on the experimental results it can be concluded that the influence of part position before welding is significant for geometrical deviation after welding. Furthermore, a working procedure for a completely virtual geometry assurance process for welded assemblies is outlined. In this process, part variations, assembly fixture variations and welding induced variations are important inputs when predicting the capability of the final assembly.

  • 2004.
    Xin, Zhu
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Improvement of Automated Guided Vehicle's image recognition: Object detection and identification2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Automated Guided Vehicle(AGV) as a kind of material conveying equipment has been widely used in modern manufacturing systems. [1] It carries the goods between the workshop along the designated paths. The ability of localization and recognizing the environment around themselves is the essential technology. AGV navigation is developed from several technologies such as fuzzy theory, neural network and other intelligent technology. Among them, visual navigation is one of the newer navigations, because of its path laying is easy to maintain, can identify variety of road signs. Compared with traditional methods, this approach has a better flexibility and robustness, since it can recognition more than one path branch with high anti-jamming capability. Recognizing the environment from imagery can enhance safety and dependability of an AGV, make it move intelligently and brings broader prospect for it. University West has a Patrolbot which is an AGV robot with basic functions. The task is to enhance the ability of vision analysis, to make it become more practical and flexible. The project is going to add object detection, object recognition and object localization functions on the Patrolbot. This thesis project develops methods based on image recognition, deep learning, machine vision, Convolution Neural Network and related technologies. In this project Patrolbot is a platform to show the result, we can also use this kind of program on any other machines. This report generally describes methods of navigation, image segmentation and object recognition. After analyzing the different methods of image recognition, it is easy to find that Neural Network has more advantages for image recognition, it can reduce the parameters and shorting the training and analyzing time, therefore Convolution Neural Network was introduced detailly. After that, the way to achieve image recognition using convolution neural network was presented and in order to recognize several objects at the same time, an image segmentation was also presented here. On the other hand, to make this image recognition processes to be used widely, the ability of transfer learning becomes important. Therefore, the method of transfer learning is presented to achieve customized requirement.

    Fulltekst (pdf)
    fulltext
  • 2005.
    Xin, Zhu
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Wang, Yimin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Quality assurance of nailed pallet2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This thesis project is about quality assurance of nailed pallet, which is suggesting and evaluating a solution able to detect unknocked nails in a pallet at the company AvenPallen.

    The company AvenPallen is responsible for the production of different kinds of wood products, and these products are usually nailed in a robot cell. Due to variation in the wood, like unevenness of the density and tilt and twist of the boards, the nail may not be completely driven into the wood. This can results in an uneven smoothness of the pallet surface, and the production is unable to meet the requirements of customers and cause waste. To solve this problem the company AvenPallen manages to seek some systems to achieve quality assurance process in nails.

    The project has suggested four possible systems for detecting unknocked nails in a pallet. The suggested systems are mechanical inspection system, optical inspection system, vision technique system and 3D laser scanning system. By consider the situation of the company AvenPallen, there has been two improved system which are: optical inspection system and shadow inspection system. The optical inspection system uses the optical sensor to measure the height of nail to guarantee the quality of pallets. The shadow inspection system uses a CCD camera and a light to get some figures to measure the height of nails to ensure the quality of pallets. The two improved systems have been evaluated through tests. A suggestion of a possible analysis system is also included in the report.

    The report will give the analysis and result for the evaluation experiments and show that the shadow inspection system is a suitable inspection system with the possibility to analyse the measured data.

  • 2006.
    Xu, Fenglei
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för Matematik, Data- och Lantmäteriteknik.
    Performance evaluation and comparison of Dual-NIC computer Optiplex 780 with Cisco 2901 router2018Independent thesis Basic level (university diploma), 5 poäng / 7,5 hpOppgave
    Abstract [en]

    Evaluation of the dual-NIC computer Dell Optiplex 780 (henceforth referred to as PCR1) compared with Cisco 2901 router regarding performance.

    Both devices are tested to show maximum throughput with increasing numbers of parallel links. A Cisco Catalyst 2960G switch is used to provide more access ports. The software Iperf is used throughout the tests as both traffic generator and throughput measuring tool, meanwhile the software Dstat on PCR1 is used for CPU usage measuring. PCR1 and Cisco 2901 are tested separately. A few basic tests are performed in phase 1 to discover the maximum throughput between the devices' interfaces. In phase 2, additional client computers are added on one side of the router device, one pair at a time. All these clients receive max-load traffic simultaneously from a single server computer, which reside on the other side of the router. Phase 2 tests are meant to investigate how well the router devices handle max-load traffic in a situation where there are multiple clients, whether they prioritize any traffic or function abnormally.

    After both phases are done, an analysis of the collected data is presented, both devices's performance and differences between them will be analysed.

  • 2007.
    Yan, Nannan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Safe Human Robot Collaboration: By using laser scanners, robot safety monitoring system and trap routine speed control2016Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Nowadays, robot is commonly used to perform automation tasks. With the trend of low volume and customised products, flexible manufacturing is introduced to increase working efficiency and flexibility. Therefore, human robot collaboration plays an important role in automation production and safety should be considered in the design of this kind of robot cell. This work presents the design of safe human robot collaboration by equipping an industrial robot cell with SICK laser scanners, safety monitoring system and trap routine speed control. It also investigates the reliability of RGB-D camera for robot safety. This work aims to find a safety robot system using standard industrial robot for human robot collaboration. The challenge is to ensure the operator's safety at all times. It investigates safety standards and directives, safety requirements of collaboration, and related works for the design of collaborative robot cell, and makes risk assessment before carrying out the valuation. Based on literature review, it gives the concept of layout design and logic for slow down and resume of robot motion. The speed will be first reduced to manual speed and then zero speed depending on the distance between the human and the robot. Valuation and verification are made in the proposed safe solution for human robot collaboration to test the reliability and feasibility. This project realizes the automatic resume that the robot can con-tinue working without manually pressing reset button after the operator leaves the robot cell if there is no access to the prohibited area. In addition, it also adopts the manual reset at the same time to ensure the safety when people access the prohibited area. Several special cases that may happen in the human robot collaboration are described and analysed. Furthermore, the future work is presented to make improvements for the proposed safety robot cell design.

    Fulltekst (pdf)
    fulltext
  • 2008.
    Yehorov, Yuri
    et al.
    Center for Research and Development of Welding Processes, Federal University of Uberlandia, Uberlândia, Brazil.
    da Silva, Leandro João
    Center for Research and Development of Welding Processes, Federal University of Uberlandia, Uberlândia, Brazil.
    Scotti, Americo
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV). Center for Research and Development of Welding Processes, Federal University of Uberlandia, Uberlândia, Brazil.
    Balancing WAAM Production Costs and Wall Surface Quality through Parameter Selection: A Case Study of an Al-Mg5 Alloy Multilayer-Non-Oscillated Single Pass Wall2019Inngår i: Journal of Manufacturing and Materials Processing, E-ISSN 2504-4494, Vol. 3, nr 2, s. 1-19Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The purpose of the study was to propose a strategy to assess the potential reduction of the production cost during wire+arc additive manufacturing (WAAM) based on the combination of wire feed speed (related to deposition rate) and travel speed (related to deposition time). A series of experiments, using a multilayer-non-oscillated single pass wall made of an Al-Mg alloy, was conducted. The quality of the wall was assessed through the lateral surface waviness and top layer undulation. The concepts of Surface Waviness and Buy-to-Apply indices were introduced. Initially, the range of travel speed (TS) that provided layers with acceptable quality was determined for a given wire feed speed (WFS), corresponding to a constant current. Then, the effect of the increase of production capacity of the process (though current raising, yet maintaining the ratio WFS/TS constant) on the wall quality for a given condition within the TS range was assessed. The results showed that the useful range of TS prevents too rough a waving surface below the lower limit and top surface undulation over the higher limit. However, inside the range, there is little quality variation for the case under study. Finally, simulations of deposition time were developed to demonstrate the weight of the TS on the final deposition time and wall quality as a function of a target wall width. This respective weight showed the existence of a complex and unpredictable, yet determined, power of a combination of TS, target wall geometry, and dead time between subsequent layers. It was verified to be possible to find optimized TS as a function of different target geometries. 

    Fulltekst (pdf)
    BalancingWAAM
  • 2009.
    Yehorov, Yurii
    et al.
    Federal University of Uberlandia (UFU),Center for Research and Development of Welding Processes, Laprosolda, Uberlândia, MG 38408-100, Brazil.
    da Silva, Leandro João
    Federal University of Uberlandia (UFU),Center for Research and Development of Welding Processes, Laprosolda, Uberlândia, MG 38408-100, Brazil.
    Scotti, Americo
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV). Federal University of Uberlandia (UFU),Center for Research and Development of Welding Processes, Laprosolda, Uberlândia, MG 38408-100, Brazil.
    Exploring the use of switchback for mitigating homoepitaxial unidirectional grain growth and porosity in WAAM of aluminium alloys2019Inngår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 104, nr 1-4, s. 1581-1592Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, an alternative approach to prevent unidirectional grain growth in wire + arc additive manufacturing (WAAM) is proposed and assessed, by moving cyclically the torch forward and backward, likewise the welding technique known as switchback. A series of tests were planned with CMT (cold metal transfer) process to compare three wall-like build-ups, which uses different deposition patterns, namely, in one-way direction, reverse direction, and switchback. The same equivalent travel speed and number of deposited layers were kept among them. Longitudinal sections were taken to identify the grain growth behaviour. Finally, samples were removed from the walls for porosity evaluation. The results confirmed the characteristics of unidirectional grain growth, when one-way direction condition was employed, and the break of growth direction between layers, when reverse direction was used, yet a zig-zag pattern became present. Differently, the application of switchback showed no preferential or unidirectional grain growth, suggesting less anisotropy of mechanical properties. In addition, switchback reduced porosity. © 2019, The Author(s).

    Fulltekst (pdf)
    fulltext
  • 2010.
    Yousofi, My
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för Matematik, Data- och Lantmäteriteknik.
    Lantmäterimyndighetens yttranden under samråd och granskningstiden samt kommunernas ställningstagande2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detaljplaner används av kommuner som ett sätt att reglera användningen av mark- och vattenområden. Plankartan som hör till detaljplanen är det juridiska dokumentet där kommunen använder sig av planbestämmelser vid utformningen av planområdet. Till plankartan följer det en planbeskrivning som anger syftet och redovisar hur planen ska genomföras och vilka konsekvenser den har på sakägare, miljön och andra som kan komma att beröras av detaljplanen.

    Vid bristfälliga planbestämmelser och planbeskrivningar kan konsekvenserna för de drabbade medföra kostsamma och utdragna processer. Enligt tidigare studier innehöll 17 % av antagna detaljplaner olämpliga planbestämmelser.

    Enligt tidigare bestämmelser så var kommunen inte tvungen att samråda med lantmäterimyndigheten vid alla planförfaranden. Lantmäterimyndighetens roll var under samrådet att verka för att planbestämmelser som kunde påverka det fastighetsrättsliga genomförandet var utformade på ett ändamålsenligt sätt. Lantmäterimyndighetens roll ändrades dock i samband med den lagändring som trädde i kraft 1 januari 2015. Regeringen ville effektivisera plangenomförande och detta ledde till att lantmäterimyndigheten fick en tydligare och utökad roll i planprocessen.

    Denna studie har som syfte att undersöka hur kommunernas ställningstagande till yttranden från lantmäterimyndigheten i samband med samråd och granskningstiden ser ut. Resultatet efter samråd visar att 12 % av detaljplanerna innehöll brister som påtalats av lantmäterimyndigheten men som kommunerna inte åtgärdat. Efter granskningstiden så gick procentandelen ner till 7 % av detaljplanerna. Vid granskning om det var någon skillnad i ställningstaganden mellan kommuner med kommunal lantmäterimyndighet och kommuner med statlig lantmäterimyndighet visade undersökningen att det inte förekom några större skillnader. Studien tyder på att kommunerna lyssnar på de synpunkter och råd lantmäterimyndigheten framför och följaktligen åtgärdar påtalade brister. Detta i sin tur leder förhoppningsvis till ett effektivare plangenomförande.

    Fulltekst (pdf)
    fulltext
  • 2011.
    Yu, Huanyu
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för Industriell ekonomi, Elektro- och Maskinteknik.
    3D Scanning and Modeling with the use of a Mobile Robot2017Independent thesis Advanced level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [en]

    In recent years, the number of mobile robot has increased rapidly. They can not only be used for carrying out tasks in hostile work environment, but also make people's daily life convenient. In the meantime, the rise of 3D technology has changed people's life with its applications in the fields of industrial life and daily life. Therefore, the combination of 3D technology and mobile robot has enormous potentials.

    The objective of this project is to create a model of an object or indoor environment with the help of a mobile robot. A 3D scanner which can be attached on a mobile robot will be used for scanning. With the depth information collected, the point clouds can be gotten. The basic way of reconstructing the model is called Kinect Fusion, it uses Kinect camera to scan the area and creates a model with help of Iterative Closest Point algorithm and Truncated signed distance function which will be introduced in section 2.5. The registration of the point clouds and the localization of the camera can be realized by using ICP algorithm. The software which is used to implement these methods is Visual Studio 2012 with OpenCV and KinectFusion library.

    As the camera should be able to be used on any kind of robot, the aim of these tests is to find a better way to get a high quality model of the area. In this paper, two main experiments have been done. One of them is about scanning a target object from different distances. There will be errors between object actual size and its model size. And the relationship between the errors and the distances will be found out. The other one is focused on the movement of the camera. There are two scenarios in this experiment. The first one is to move the camera with different speed and the other scenario is to scan an object by moving the camera around the object. The result shows that the robot attached with the camera should move slowly so that the camera can capture enough frame images for the model. And keep scanning one object by moving the camera around it can't make the model looks better but worse.

  • 2012.
    Yu, Liang
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för Industriell ekonomi, Elektro- och Maskinteknik.
    Automatic obstacles avoidance pickup and placement path generation achievement with scanning of environment for an industrial robot2019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Industrial robots are widely used in modern industry fields because of the development of robot technology. In robot palletizing or bin-picking application, robot needs to automatically generate path for achieving robot picking and placing operation even if there exist obstacles. This project is to design and test a robot system that can move without collisions in a changeable environment. And communication is realized between two computers through an industrial communication protocol.

    ROS has been chosen as a simulation platform for the robot path planning simulation as it has some independent advantages, like open-source, supporting multiple programming languages, integrating a lot of open source tools and advanced algorithms. ROS MoveIt! software is used for motion planning, operation control, 3D perception, kinematic solution, collision detection, and so on. Through RRT method, robot path planning is achieved and through Flexible Collision Library, collision detection is achieved. For robot system test experiments and results, taking ABB IRB 2600 robot as a test industrial robot, a robot simulation system in ROS is designed and set up to realize obstacles free picking and placing path planning task of the robot.

    Firstly, for obtaining external obstacles information, Kinect V1 camera is used and calibrated for eliminating distortion and obtains colour image and depth image. Secondly, by using Point Cloud Library, the images are transformed to point cloud images with filtering for eliminating noise. Thirdly, by using OctoMap library, the scene including obstacles are created to 3D occupancy map. Furtherly, according to the map, robot obstacles avoidance pickup and placement operation is achieved in ROS.

    Finally, for testing and evaluating the system, the robot model, a pickup object and an obstacle model are created in ABB RobotStudio software which is the same as ROS's and further achieves co-simulation motion in ROS and ABB RobotStudio by ROS TCP/IP socket program. By running path planning in ROS, the robot achieves obstacle avoidance path planning and pickup and placement operation in ABB RobotStudio.

  • 2013.
    Yusuf, Abdisalam
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för elektro, lantmäteri och naturvetenskap.
    Effektivare bagagehantering vid Mogadishu´s flygplats2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I detta examensarbete var huvudmålet att ta fram förbättringsförslag som gör det möjligt för SKA International Group att åstadkomma utjämnad genomloppstid vid Mogadishus flygplats. SKA International Group är ett logistik företag som tog över ansvaret på flygplatsen tre år sedan. Företagets uppdrag var att bygga upp flygplatsen och göra den till en av dem bästa i regionen. Efter tre år har flygtrafiken på flygplatsen ökat markant vilket medförde att bagagehanteringen blev ett stort problem. Företaget har inte skaffat sig nyare och modernare utrustning för att klara av trycket av bagaget som ökar i antal för varje dag som går. Examensarbetet bestod dels av ett teoriavsnitt med en litteraturstudie utifrån nutida forskning och även en kvalitativ undersökning genom intervjuer med ett antal personer på företaget. Det görs även en kartläggning på företagets processflöda genom att använda ett verktyg som heter värdeflödesanalys. Med hjälp av analysen identifieras det vad som är värdeskapande och icke värdeskapande för bagagehanteringen. Genom analysen identifierats det även förbättringsområden som var kritiska för att kunna reducera ledtiden. På slutet av detta examensarbete togs det fram ett antal förbättringsförslag som kan skapa förutsättningar för en framgångsrik förändring till det bättre. Ett av de viktigaste förbättringsförslagen som framtogs är hur företaget kan åstadkomma ledtidsreduktion vid flygplatsen

  • 2014.
    Yücel, GIzem
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för lantmäteriteknik och matematik.
    Sjöobodsupplåtelser: kartläggning och reflektioner2012Independent thesis Basic level (university diploma), 10 poäng / 15 hpOppgave
    Abstract [sv]

    I uppdrag av Kungälvs kommun har en kartläggning gjorts mellan olika kommuner inom Bohuslän samt Göteborg som senare ska fungera som planeringsunderlag för kommunen. Kartläggningen bygger på ett frågeformulär som har skickats till kommunerna Göteborg, Tanum, Öckerö, Tjörn, Orust, Strömstad, Lysekil, Sotenäs och Kungälv. Innan frågeformuläret skickades in gjordes en omfattande litteraturstudie om kommunernas hantering av sjöbodar.

    Utgångspunkten med kartläggningen har varit att ta reda på hur kommunerna hanterar sina sjöbodar, med avseende på exempelvis deras upplåtelseformer, upplåtelsetider, avgifter, avtalsvillkor, användning och styrning med hjälp av detaljplan, bygglov och tillsyn, kommunens egna reflektioner på hur deras hantering fungerar m.m.

    Teoridelen består av allmän information om:

    - Sjöbodar, definitioner och användning.

    - Arrende, då den är en utav de vanligaste upplåtelseformerna för sjöbodar, med avseende på anläggningsarrende och lägenhetsarrende.

    - Hyra, är en annan form av upplåtelse som används i ett par kommuner.

    - Hur det kan fungera när kommunen äger marken som ska arrenderas

    - En gemensam sjöbodspolicy som tillämpas i ett fåtal kommuner.

    Resultatet är en sammanställning av den information som har tagits reda på genom frågeformulärens svar. Svaren från frågeformulären informerade bland annat om att det finns mellan 25 stycken till 1200 stycken sjöbodar i kommunerna och att upplåtelse av sjöbodar sker vanligtvis genom arrende men också till viss del genom hyra. Upplåtelsetiden brukar vara på ett år med automatiskt förlängning. Avgifterna ligger på mellan 887 kr upp till 2800 kr. De flesta kommunerna försöker också styra sjöbodarnas utformning och användning genom avtalsvillkor, regler och bygglov.

    Den generella uppfattningen som kartläggningen resulterar i är att de flesta kommunerna vill uppdatera sina sjöbodshanteringar. Resultatet tydliggör att det finns likheter och skillnader i tillämpningen av sjöbodsupplåtelser mellan kommunerna. Vissa kommuner har exempelvis inga fördelningsregler för vem som ska ha rätt till en sjöbod i kommunen. I dessa fall får arrendatorn själv hitta en lämplig köpare av boden och detta leder till minskad tillsyn och kontroll från kommunen över vem som tillträder arrendet.

    Det finns inte så många kommuner som använder en detaljplan för att styra användning och utformning av en sjöbod, vilket skulle kunna styras bättre om kommunerna ökade användningen av detaljplaner för sjöbodar.

    EXAMENSARBETE

    Efter genomförd kartläggning blir slutsatsen att en kommun kan ha en bra hantering av sjöbodar om det finns en sjöbodspolicy som upplyser om vad en sjöbod är och hur den ska användas, tillämpningsregler från kommunerna som kan vara lättillgängligt för allmänheten, ett arrendeavtal som har sjöbodspolicyn och tillämpningsreglerna som komplement och en detaljplan med planbestämmelser för hur sjöbodarna och marken kring sjöbodarna ska hanteras.

    Fulltekst (pdf)
    Sjöbodar
  • 2015.
    Zachrisson, Jan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik.
    Quantitative Characterisation of packet Crystallography in high strength steel weld metals2012Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 2016.
    Zachrisson, Jan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik.
    Börjesson, J
    ESAB AB.
    Karlsson, Leif
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik.
    Role of inclusions in formation of high strength steel weld metal microstructures2013Inngår i: Science and technology of welding and joining, ISSN 1362-1718, E-ISSN 1743-2936, Vol. 18, nr 7, s. 603-609Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A series of high strength weld metals with varying Al content are studied. The inclusions are characterised using energy dispersive X-ray analysis and electron diffraction. The tendency for alignment of the microstructure is characterised quantitatively using electron backscatter diffraction and a recently developed post-processing technique. Correlation is found between the inclusion phases present and the amount of aligned neighbouring grains in the microstructure. It is shown that amorphous Si-Al oxides form at low Al weld metal contents and an Mg-Al spinel at higher contents. The former is associated with less alignment of the microstructure and therefore higher impact toughness. The effect of these inclusions on the formation of the microstructure is discussed.

  • 2017.
    Zachrisson, Jan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd Forskningsmiljön industriprocesser.
    Börjesson, Johan
    ESAB AB, Lindholmsallén 9, Box 8004, SE-40277 Gothenburg.
    Karlsson, Leif
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    A new EBSD based methodology for the quantitative characterisation of microstructures formed by displacive fcc–bcc transformations2013Inngår i: Micron, ISSN 0968-4328, E-ISSN 1878-4291, Vol. 45, nr February, s. 45-54Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This work is concerned with a new methodology that can be used to quantify the degree to which grains in the microstructure are aligned in the form of packets. The methodology is based on a crystallographic definition of the term packet which is used to deduce the theoretically ideal misorientations of intra-packet grain boundaries. A misorientation distribution obtained from extensive EBSD mapping can thus be split into intra- and inter-packet misorientations and the corresponding fractions can be determined by integration. The theoretical framework of the methodology is explained and a step-by-step description of the procedure is given. Results from a trace analysis are provided to justify the assumptions made regarding habit plane and examples are included showing how the grain boundary network can be split into two separate parts, one for lath boundaries and the other for packet boundaries. Moreover, example weld metal microstructures along with the corresponding misorientation distributions as well as quantitative values of the microstructures are presented.

  • 2018.
    Zafer, Yunus Emre
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Encapsulation of Surface Defects in Electron Beam Melting produced Alloy 7182019Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Electron beam melting (EBM) is a rapidly growing metal additive manufacturing technology due to its ability to manufacture near net shape metal parts, especially from high-value materials like Alloy 718. Defects like porosities in the EBM manufactured Alloy 718 are inevitable to some extent and are of concern as they can degrade the mechanical properties of the part. Therefore, EBM manufactured Alloy 718 is typically subjected to post-processing to improve the properties of the as-built material in order to achieve the required performance of the parts. Hot isostatic pressing (HIP) is usually employed to close the defects. Nevertheless, it is widely known that the HIP treatment cannot close the open defects, which are connected to the environment of the material.

    Thus, the aim of this study was to investigate if the open defects in EBM built Alloy 718 can be encapsulated by application of a coating on the surface, to effectively close these during HIP treatment. The EBM manufactured Alloy 718 specimens were coated on two sides by high-velocity air fuel (HVAF) spraying using Alloy 718 powder and were HIPed. X-ray computed tomography analysis of the defects in the coated sample before and after HIP treatment showed that some of the defects connected to the EBM material surface were effectively encapsulated by the coating as they were closed after HIP treatment. However, some of these 'surface connected' defects were retained. The reason for such remnant defects could be their connection to the environment through the gap between the coating and the EBM material. The gap could have provided the path for argon infiltration from the uncoated sides during the HIP treatment, thereby hindering complete densification of the specimen. In addition, the lack of fusion defects were typically associated with inclusions, which could also be prevented their complete closure during HIP treatment.

  • 2019.
    Zafer, Yunus Emre
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Goel, Sneha
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ganvir, Ashish
    Research & Technology, Department of Process Engineering, GKN Aerospace Engine Systems AB, 461 81 Trollhättan, Sweden.
    Jansson, Anton
    Örebro University, School of Science and Engineering, 701 82 Örebro, Sweden.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Encapsulation of Electron Beam Melting Produced Alloy 718 to Reduce Surface Connected Defects by Hot Isostatic Pressing2020Inngår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 13, nr 5, artikkel-id 1226Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Defects in electron beam melting (EBM) manufactured Alloy 718 are inevitable to some extent, and are of concern as they can degrade mechanical properties of the material. Therefore, EBM-manufactured Alloy 718 is typically subjected to post-treatment to improve the properties of the as-built material. Although hot isostatic pressing (HIPing) is usually employed to close the defects, it is widely known that HIPing cannot close open-to-surface defects. Therefore, in this work, a hypothesis is formulated that if the surface of the EBM-manufactured specimen is suitably coated to encapsulate the EBM-manufactured specimen, then HIPing can be effective in healing such surface-connected defects. The EBM-manufactured Alloy 718 specimens were coated by high-velocity air fuel (HVAF) spraying using Alloy 718 powder prior to HIPing to evaluate the above approach. X-ray computed tomography (XCT) analysis of the defects in the same coated sample before and after HIPing showed that some of the defects connected to the EBM specimen surface were effectively encapsulated by the coating, as they were closed after HIPing. However, some of these surface-connected defects were retained. The reason for such remnant defects is attributed to the presence of interconnected pathways between the ambient and the original as-built surface of the EBM specimen, as the specimens were not coated on all sides. These pathways were also exaggerated by the high surface roughness of the EBM material and could have provided an additional path for argon infiltration, apart from the uncoated sides, thereby hindering complete densification of the specimen during HIPing.

    Fulltekst (pdf)
    fulltext
  • 2020.
    Zaikovska, Liene
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    Konstruktion och formgivning av diagnos- och testverktyg2009Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Dagens biltillverkare tillverkar allt mer avancerade och komplexa elektroniska system i sina fordon. Det finns mellan 40 och 70 elektroniska styrenheter i en bil. Styrenheterna kontrollerar och reglerar allt från komplicerade bränslesystem till sätesuppvärmning. För att hitta elektroniska fel snabbt och säkert är funktionell och enkel diagnos- och testutrustning en bra investering för verkstäderna. Cabeco AB tillverkar och utvecklar diagnos- och testutrustningar. Genom att förnya designen och användarvänligheten och genom undersökning av mer miljövänliga material, utvecklades ett diagnosverktyg, Break-Out-Box. Med hjälp av etablerade produktutvecklingsmetoder togs fyra olika koncept fram. Två koncept valdes ut för fortsatt utveckling och endast ett av koncepten utvecklades fullständigt. En prototyp av den tillverkades. Resultatet av det nya konceptet visar att materialåtgången har minskats, monteringstiden blir betydligt kortare, verktygskostnaderna blir lägre, antalet monteringsoperationer blir färre, vilket sammantaget ger betydligt lägre tillverkningskostnader. Det har också lett till att de viktigaste kundkraven blev uppfyllda.

    Fulltekst (pdf)
    FULLTEXT01
  • 2021.
    Zaikovska, Liene
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik.
    Simulation of a sheet metal leading edge for a three piece vane using bending and deep-drawing2013Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Fulltekst (pdf)
    fulltext
  • 2022.
    Zampal, Luigi
    et al.
    University of Trieste, Department of Mathematics and Geoscience, Trieste, Italy.
    Tenzer, Robert
    Hong Kong Polytechnic University, Department of Land Surveying and Geo-Informatics, Hong Kong.
    Eshagh, Mehdi
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för Matematik, Data- och Lantmäteriteknik.
    Pitonak, Martin
    University of West Bohemia, New Technologies for the Information Society (NTIS), Faculty of Applied Sciences, Czech Republic.
    Evidence of mantle upwelling/downwelling and localized subduction on Venus from the body-force vector analysis2018Inngår i: Planetary and Space Science, ISSN 0032-0633, E-ISSN 1873-5088, Vol. 157, s. 48-62Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Considering that Venus has a size very similar to Earth, thermal evolution of both planets should be comparable. Nonetheless, there is no clear evidence of plate tectonics or plate motions on Venus. Instead, various surface deformations attributed to volcanism, resurfacing, localized subduction and other geologic processes were recognized on the planet. In this study we attempt to classify the origin of lithospheric forces on Venus based on using topographic and gravity information. For this purpose, we also estimate the Venusian crustal thickness. In agreement with findings from previous studies, the signature of past or recent global tectonism in the body-force vector pattern on Venus is absent, while exhibiting only regional anomalies. The maximum intensity inferred in the Atla and Beta Regios is likely attributed to mantle upwelling. This is also confirmed by the gravity-topography spectral correlation and admittance analysis that shows the isostatic relaxation of these volcanic regions. The regional body-force pattern in the Bell Regio suggests that a much less pronounced force intensity there is possibly related to crustal load of lava flows. Elsewhere, the body-force intensity is relatively weak, with slightly more pronounced intensity around the Ishtar Terra and the Arthemis Chasmata. The body-force pattern in the Arthemis Chasmata supports the hypothesis that coronae structures are the result of mantle upwelling and the subsequent (localized) plume-induced subduction with only limited horizontal crustal motions. The prevailing divergent pattern of body-force vectors in the Ishtar Terra region suggests the presence of tensional forces due to the downwelling mantle flow that is responsible for a crustal thickening along the Freyja and Maxwell Montes. Except for the Atla and Beta Regios where the isostasy is relaxed by the (active) mantle plumes, the crustal thickness is spatially highly correlated with the topography, with a thin crust under the plains and a thick crust under the plateaus. The maximum Moho depth under the Maxwell Montes in the Ishtar Terra exceeds 90 km.

  • 2023.
    Zhang, Cheng
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Influence of surface roughness on thermography measurement2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This university Bachelor's Thesis was performed to explore the influence of surface roughness on the thermography measurement.

    Thermography is a non-destructive testing method which can be used to detect cracks. However, it is hard to define how the surface roughness influences the emissivity and the result of a thermography measurement, as well as how the angle of the excitation source influences the result. Therefore, this work aims to define how the heating angle and surface roughness influence the thermography measurement, define the relationship between surface roughness and emissivity for the same crack, and define the influence of the angles which composed of the heating source, the direction of crack and the direction of surface roughness on thermography measurement.

    In this report, the theories of radiation and Signal-to-noise ratio (SNR) were explained, clearly. Also, two kinds of experiments were set up. One is focus on how the heating angle influence the thermography measurement, the other is focus on how the angle of the heating source, in relation to the crack direction and the direction of surface roughness, influence the SNR value.

    The conclusions of these experiments are that the heating of a crack increases as the angle decreases (from wide side to narrow side) and the angle ofincreases (from horizontal to vertical). Moreover, the SNR value decreases as the surface roughness increases. For the same surface roughness, the SNR value increases with increased crack angle (0°, 45° or 90°) and with decreased sample position angle (horizontal, 45°or vertical). What is more, the higher surface roughness, the larger the influence of the crack angle and the sample position angle. Finally, when the surface is polish, the crack angle and the sample position angle does not have any influence.

    Fulltekst (pdf)
    fulltext
  • 2024.
    Zhang, Cheng
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Robotic 3D friction stir welding: T-butt joint2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This Master Thesis was performed in terms of robotic three dimensional friction stir welding with T-butt joint. Friction stir welding (FSW) is a solid state welding method that achieves the weld temperature by friction of a rotating non-consumable tool with the workpiece. Science and technology fast developing requires for higher seam quality and more complex welding joint geometry like 3D welds. In order to acquire high productivity, capacity and flexibility with acceptable cost, robotic FSW solution have been proposed. Instead of the standard FSW machine, using a robot to perform complicated welds such as, three-dimensional.

    In this report, a solution for weld a 3D T-butt joint, which located in an aluminium cylinder with 1.5 mm thickness using a robot, was developed. Moreover, two new paths were investigated in order to avoid the use of two welds to perform this type of joint. The paths were tested on 2D and on 3D (with a 5050 curvature radius) geometries. Both paths had good results. What is more, the parameter developing methods of FSW process, which is composed of necessary parameter setting, positional compensation was introduced. Specially,the study demonstrates how complicate geometry can be welded using a robot. Also,it shows that TWT temperature control is able to acquire high quality 3D welds. In addition, an analysis of the 2D welding and 3D welding was performed, which exposed that, keeping exactly the same welding conditions, higher lateral forces on the tool were found during 3D welding. Basis on the special case in this paper, when the tool goes like "climbing" the sample, the suffering force of tool decreasing with increasing the height(Z position); nevertheless, when the tool goes like "downhill", the suffering force of tool decreasing with decreasing the height (Z position). What is more, in 2D weld, increasing the downforce (Fz) results increasing the lateral forces which can be Fx and/or Fy.

    Finally, the future works suggestions were presented in terms of (1) performing the new paths into a real cylinder, (2) performing tensile test on the paths and comparing it with conventional path which weld twice, (3) researching how the downforce (Fz) influence the Fx and Fy during welding of different 3D geometries, (4) how the cooling rate of backing bar influence the seam quality when it is use the same welding parameters and (5) the effect of performing welds in the same welding temperature achieved with different combination of the tool rotational speed and downforce on the material properties

    Fulltekst (pdf)
    fulltext
  • 2025.
    Zhang, Jing
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Conceptual Design of a Novel Continuous Nanoparticle Production Equipment for Energy Efficient Sintering and Additive Manufacturing2018Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Materials in nanoscale possess interesting features such as depression of melting point, increased chemical reactivity, improved mechanical, electrical and thermal properties. Today, nanoparticles (NPs) are generally produced using chemical synthesis routes and other top down methods. These processes suffer generally from issues such as low production yield and require complex precursors that may have large environmental concerns. NPs, especially spherical NPs, are very interesting in bringing down sintering temperature for sinter alloys and act as nucleation sites for crystal growth in, for instance, additive manufacturing processes. These features lead to decreased energy consumption and improved mechanical performance of additively manufactured products. Therefore, manufacturing of NPs in large scale is of great interest for future industrial development.

    The purpose of the present thesis work is to carry out a feasibility design study for a novel nanoparticle manufacturing equipment concept using a novel two coupled axis concept for producing NPs in larger quantities.

    The method is based on Consumable Electrode Direct Current Arc (CEDA, also called spark erosion) using two vertically aligned parallel electrodes, thus significantly increasing the yield of the NPs production. Before the start of the design work, a theoretical study was carried out to understand the state-of-the-art of the nanoparticle manufacturing processes available. It was followed by a novel design concept for a new equipment that can dramatically increase the yield of the NPs production compared to the state-of-the-art. The work is carried out using the Software Solidworks2016. A 3D model of the new machine concept using the novel design was built. A simulation of the control system based on the Software Proteus was carried out.

    This novel equipment can potentially offer continuous and larger scale and production of NPs which is useful for energy efficient sintering and for efficient control of grain size in additive manufacturing process, thus making a better product in the fast-growing additive manufacturing business sector.

  • 2026.
    Zhang, Pimin
    et al.
    Linköping University, Department of Management and Engineering, Linköping, SE-58183, Sweden.
    Sadeghi, Esmaeil
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Chen, Shula
    Linköping University, Department of Physics, Chemistry, and Biology, Linköping, SE-58183, Sweden.
    Li, Xin-Hai
    Siemens Industrial Turbomachinery AB, Finspång, SE-61283, Sweden.
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Chen, Weimin
    Linköping University, Department of Physics, Chemistry, and Biology, Linköping, SE-58183, Sweden.
    Buyanova, Irina A.
    Linköping University, Department of Physics, Chemistry, and Biology, Linköping, SE-58183, Sweden.
    Peng, Ru L.in
    Linköping University, Department of Management and Engineering, Linköping, SE-58183, Sweden.
    Effects of surface finish on the initial oxidation of HVAF-sprayed NiCoCrAlY coatings2019Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 364, s. 43-56Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oxide scale formed on HVAF-sprayed NiCoCrAlY coatings and the effect of surface treatment were investigated by a multi-approach study combining photo-stimulated luminescence, microstructural observation and mass gain. The initial oxidationbehaviour of as-sprayed, polished and shot-peened coatings at 1000 °C is studied. Both polished and shot-peened coatings exhibited superior performance due to rapid formation of α-Al2O3 fully covering the coating and suppressing the growth of transient alumina, assisted by a high density of α-Al2O3 nuclei on surface treatment induced defects. Moreover, the fast development of a two-layer alumina scale consisting of an inward-grown inner α-Al2O3 layer and an outer layer transformed from outward-grown transient alumina resulted in a higher oxide growth rate of the as-sprayed coating.

  • 2027.
    Zhang, Pimin
    et al.
    Linköping University, Department of Management and Engineering, Linköping, Sweden.
    Sadeghimeresht, Esmaeil
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Peng, Ru Lin
    Linköping University, Department of Management and Engineering, Linköping, Sweden.
    Li, Xin-Hai
    Siemens Industrial Turbomachinery AB, Finspång, Sweden.
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Joshi, Shrikant
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Johansson, Sten
    Linköping University, Department of Management and Engineering, Linköping, Sweden.
    Isothermal oxidation behavior of HVAF-sprayed NiCoCrAlY coatings: Effect of surface treatment2017Inngår i: Proceedings of the International Thermal Spray Conference & Exposition (ITSC 2017), New York: Curran Associates, Inc , 2017, Vol. 1, s. 456-461Konferansepaper (Fagfellevurdert)
    Abstract [en]

    NiCoCrAlY coatings are widely used as bond coats for ceramic thermal barrier coatings (TBCs) andoxidation and corrosion protective overlay coatings in industrial gas turbines. High temperature oxidation behaviour of NiCoCrAlYs has a great influence on the coating performance and lifetime of TBCs. A promising route to decrease the oxidation rate of such coatings is post-coating surface modification which can facilitate formation of a uniform alumina scale with a considerably slower growth rate compared to the as-sprayed coatings. In this work, the effect of surface treatment by means of shot peening and laser surface melting (LSM) on the oxidation resistance of high velocity air-fuel (HVAF) sprayed NiCoCrAlY coatings was studied. Isothermal oxidation was carried out at 1000⁰C for 1000h. Results showed that the rough surface of as-sprayed HVAF sprayed coatings was significantly changed after shot peening and LSM treatment, with a compact and smooth appearance. After the exposure, the oxide scales formed on surface-treated NiCoCrAlY coatings showed different morphology and growth rate compared to those formed on as-sprayed coating surface. The oxidation behaviour of surface treated HVAF-sprayed NiCoCrAlY coatings were revealed and discussed.

  • 2028.
    Zhang, Xiaoxiao
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    A discussion of methods and strategyfor spot welding localization calibration2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Spot welding is one of the most important welding procedures. Robots are used to perform the welding operation in dangerous and high temperature environment. This technology is to a large extent used in automotive industry to join plates. Specifically, in this work the joining of two plates of a car door is studied for the purpose of making it possible to decrease folded size and thereby materials used and as a result reduce weight of the product. There are many factors adding to uncertainty from the physical world such as noise of the welding machine, weld process or the signals, which all add up related to tolerances in control of the welding process The task of the research in this study is to control spot welding process in order to reduce tolerances and the plate folded size. A sensor system was developed and is described in this report. Universal methods based on laser scanner and cameras are introduced and the advantages and disadvantages of these are discussed. An optimized method based on universal methods with a strategy to meet the timing demands is developed. Experiments are performed to test the methods with ABB robot. The whole sensor system including the communication is built up and the algorithms are executed by programs.     The accuracy of the camera based method is tested in experiments. The result is promising and indicate feasible methods and strategy to locate the spot welding location during operation and thereby make it possible to achieve better welding quality with minimized increasing in cycle time.     Future work should be directed towards to choose a proper laser scanner and to create better mathematical model for the strategy in order to implement this in a real production environment.

  • 2029.
    Zhang, Xun
    et al.
    The University of Manchester, Henry Moseley X-ray Imaging Facility, The Henry Royce Institute, School of Materials, M13 9PL, Manchester, United Kingdom.
    Li, Chun
    State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, China; The University of Manchester, School of Materials, M13 9PL, Manchester, United Kingdom.
    Withers, Philip J.
    The University of Manchester, Henry Moseley X-ray Imaging Facility, The Henry Royce Institute, School of Materials, M13 9PL, Manchester, United Kingdom.
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Xiao, Ping
    The University of Manchester, School of Materials, M13 9PL, Manchester, United Kingdom.
    Determination of local residual stress in an air plasma spray thermal barrier coating (APS-TBC) by microscale ring coring using a picosecond laser2019Inngår i: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 167, s. 126-130Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A picosecond laser for incremental annular trench cutting is combined with digital image correlation (DIC) to extend the incremental ring-core method to the profiling of residual stress in thick (>100 μm) coatings. In this case the local residual stress in a TBC is depth profiled after exposure to 1150 °C for 190 h. The topcoat was found to be in compression with an average compressive stress of −94 ± 8 MPa which is representative of the stresses that would be generated elastically on cooling from a stress-free temperature of ~970 °C. The stress profile measurements have been validated by high-energy synchrotron X-ray diffraction measurements. © 2019

  • 2030.
    Zhang, Ye
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Simulation of a production line in Robot Studio: Modelling and simulation2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    With the development of science and technology, production system in modern factories is more complex than it used to be. In order to cut unnecessary loss and protect operators from failure, simulation plays an essential role on testing production lines. In this thesis work, the model of production lines, located in Production Technology Centre (PTC) of University West were built with NX, Autodesk Inventor and simulated with Robot studio. And the production line includes three robot cells (milling machine work cell, turning machine work cell and conveyance work cell, respectively), a gantry robot and some auxiliary equipment, i.e. tables, computers, human task console. Signals were added to make sure the model could work as reality.

    Different measurement methods were used in order to locate production line components at right positions due to their importance to the accuracy of simulation. Measurement methods were also compared with each other to show the error. For instance, the error of CAD models, measurement, and the distance error among equipment, etc.

  • 2031.
    Zhao, Y.
    et al.
    University of Manchester, School of Materials.
    Shinmi, A.
    University of Manchester, School of Materials.
    Zhao, X.
    University of Manchester, School of Materials.
    Withers, P. J.
    University of Manchester, School of Materials.
    Van Boxel, S.
    University of Manchester, School of Materials.
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Nylén, Per
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Xiao, Ping
    University of Manchester, School of Materials.
    Investigation of interfacial properties of atmospheric plasma sprayed thermal barrier coatings with four-point bending and computed tomography technique2012Inngår i: Surface and Coatings Technology, ISSN 0257-8972, Vol. 206, nr 23, s. 4922-4929Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A modified four-point bending test has been employed to investigate the interfacial toughness of atmospheric plasma sprayed (APS) yttria stabilised zirconia (YSZ) thermal barrier coatings (TBCs) after isothermal heat treatments at 1150°C. The delamination of the TBCs occurred mainly within the TBC, several to tens of microns above the interface between the TBC and bond coat. X-ray diffraction analysis revealed that the TBC was mainly tetragonal in structure with a small amount of the monoclinic phase. The calculated energy release rate increased from ~50J/m -2 for as-sprayed TBCs to ~120J/m -2 for the TBCs exposed at 1150°C for 200h with a loading phase angle about 42°. This may be attributed to the sintering of the TBC. X-ray micro-tomography was used to track in 3D the evolution of the TBC microstructure non-destructively at a single location as a function of thermal exposure time. This revealed how various types of imperfections develop near the interface after exposure. The 3D interface was reconstructed and showed no significant change in the interfacial roughness after thermal exposure. © 2012 Elsevier B.V.

  • 2032.
    ZhongYang, Gong
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Bottleneck detection through simulation software2015Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Bottleneck detection in production is essential to improve the overall manufacturing capacity. The common bottleneck detection methods have drawbacks of either practicability or accuracy. There is a recent manual methodology called bottleneck walk which is simple, accurate and easy to implement. Though it is a reliable and practical manual method, other more automated non-manual methods for detecting bottlenecks should be considered in the future. In this paper, the simulation models were built in a discrete event simulation software named Plant simulation. The models are based on real production cases where the bottleneck walk methodology had been tested. In the first case, the particular result shows that machine 2 has been the bottleneck for a long period, which is what is found in the real production. In the second case, the bottlenecks are found and the potential improvements are made on it. Though two improvement plans are made, neither of them solves the bottleneck and im-proves the system output. The plan of reducing buffer size might probably have an improve-ment on financial aspect. And further improvements on all findings remain available on models built in this paper.

  • 2033.
    Zou, Zhonghua
    et al.
    Shanghai Jiao Tong University, Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai 200240, China .
    Donoghue, Jack
    University of Manchester, School of Materials, Grosvenor Street, Manchester M1 7HS, UK .
    Curry, Nicholas
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för maskinteknik.
    Yang, Lixia
    Shanghai Jiao Tong University, Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai 200240, China .
    Guo, Fangwei
    Shanghai Jiao Tong University, Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai 200240, China .
    Nylén, Per
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Zhao, Xiaofeng
    Shanghai Jiao Tong University, Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai 200240, China .
    Xiao, Ping
    Shanghai Jiao Tong University, Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming, Shanghai 200240, China .
    A comparative study on the performance of suspension plasma sprayed thermal barrier coatings with different bond coat systems2015Inngår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 275, s. 276-282Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The performance of suspension plasma sprayed (SPS) yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) after isothermal treatment at 1150. °C was investigated. The NiCoCrAlY bond coats were applied by air plasma spray (APS) and high velocity oxygen fuel (HVOF) techniques. It was found that the microstructure of SPS TBCs depends on the surface morphology of the bond coat. The SPS TBCs with a rough APS bond coat exhibited a longer lifetime than those with a smooth HVOF bond coat. To understand this phenomenon, the evolution of the microstructure, mechanical properties and the residual stresses in the TBCs and TGO were systematically studied. Results showed that the surface roughness and oxidation behavior of the bond coat play dominant roles in the SPS TBC failure. © 2015.

  • 2034.
    Zouity, Amina
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för maskinteknik och naturvetenskap.
    Parameterstudie om lasersvetsning av en nickelbaslegering2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Examensarbetet har genomförts på Siemens Industrial Turbomachinery AB i Trollhättan,Sverige. Syftet med examensarbetet var att identifiera problem i en svetsprocess för att kunna förbättra svetskvaliteten. Baserat på statistisk försöksplanering utvärderades fyra faktorer med Design of experiments (DOE) metoden och tio experiment i materialet 2 mm hastelloy X genomfördes med Siemens fiberlaser (3D Prima Laserdyne 795). Faktorerna svetshastighet, skyddsgas, fokalpunkt och lasereffekt var de fyra svetsparametrarna som varierades i experimenten, i syfte att utvärdera faktorernas effekt på porer samt foggeometri i svetsarna. Plana testplåtar skapades till experimenten och brainstorming genomfördes med personal ifrån Siemens, för att bestämma faktorer till experimenten. För att utvärdera porer och foggeometrin röntgades, snittades, slipades och polerades testplåtarna.Foggeometrin mättes och fotograferades med mikroskop. Statistisk analys utfördes med Minitab som utvärderade de valda faktorernas effekt på porer och foggeometrin. Problem i svetsprocessen identifierades baserat på de tio experiment som genomfördes vilket var porer samt kritiska mått för foggeometrin. Ett samband för porer och foggeometrin identifierades. Sambandet var att om porer uppstår i svetsen påverkas även foggeometrin negativt, detta är dock inte statistiskt bevisat. Svetsprocessen har identifierats till att vara ostabil baserat på de statistiska analyser som genomförts. Svetsprocessen behöver utvärderas ytterligare för att identifiera de störfaktorer som påverkar stabiliteten i svetsprocessen. Ett av de tio delförsöken var närmast kriterierna för kvalitetsmässigt godkänd svetsfog. Delförsöket som förekom närmast kriterierna för kvalitetsmässigt godkänd svetsfog rekommenderades till fortsatt arbete för Siemens. De svetsparametrar som rekommenderas till att utvärderas vidare är lasereffekt samt samspelsfaktorn svetshastighet och skyddsgas, vilket kan ha en betydande påverkan på porer samt foggeometrin baserat på den statistiska analysen som genomförts med datorprogrammet Minitab.

  • 2035.
    Åkerfeldt, Pia
    et al.
    Luleå University of Technology,Division of Materials Science, Luleå, Sweden.
    Hörnqvist Colliander, Magnus
    Chalmers University of Technology, Department of Physics, Göteborg, Sweden.
    Pederson, Robert
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV). Luleå University of Technology,Division of Materials Science, Luleå, Sweden.
    Antti, Marta-Lena
    Luleå University of Technology,Division of Materials Science, Luleå, Sweden.
    Electron backscatter diffraction characterization of fatigue crack growth in laser metal wire deposited Ti-6Al-4V2018Inngår i: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 135, s. 245-256Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By additive manufacturing (AM) there is a feasibility of producing near net shape components in basically one step from 3D CAD model to final product. The interest for AM is high and during the past decade a lot of research has been carried out in order to understand the influence from process parameters on the microstructure and furthermore on the mechanical properties. In the present study laser metal wire deposition of Ti-6Al-4V has been studied in detail with regard to its fatigue crack propagation characteristics. Two specimen orientations, parallel and perpendicular to the deposition direction, have been evaluated at room temperature and at 250 °C. No difference in the fatigue crack growth rate could be confirmed for the two specimen orientations. However, in the fractographic study it was observed that the tortuosity varied between certain regions on the fracture surface. The local crack path characteristic could be related to the alpha colony size and/or the crystallographic orientation. Moreover, large areas exhibiting similar crystallographic orientation were observed along the prior beta grain boundaries, which were attributed to the wide alpha colonies frequently observed along the prior beta grain boundaries. © 2017 Elsevier Inc.

  • 2036.
    Åkesson, Martin
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för data- och elektroteknik.
    Svensson, Jimmie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för data- och elektroteknik.
    Nydesign av kommunalt corenät2014Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Detta examensarbete behandlar ett antal problem som Uddevalla kommun har i sitt corenät. Nätverket är idag uppbyggt på enbart lager2-länkar och routingen är fördelad på ett antal för ändamålet dedikerade multilayerswitchar. Dessa switchar, vars enda uppgift är att routa, är konfigurerade med enbart statiska routes. Att fördela routingen på detta sätt innebär ineffektiva trafikflöden, vilket belastar länkar och nätverksenheter onödigt mycket. Då kommunen skall byta ut och uppgradera sitt corenät, arbetas det fram ett designförslag som löser dessa problem.

    Framtagandet av designförslag för det nya corenätet har genomförts genom att i laborationsmiljö göra mätningar som jämför dagens distribuerade routinglösning med en lösning där routingen flyttas så nära källan som möjligt. Utifrån resultaten av dessa mätningar har ett designförslag arbetats fram för att optimera både routing och trafikflöden.

    Det designförslag som tagits fram bygger på Ciscos hierarkiska modell, vilket är en modell som beskriver hur ett skalbart och redundant nätverk bör byggas. I denna modell delas nätverket in i de tre lagren; core, distribution och access. I förslaget effektiviseras routingen genom att den flyttas till distributionslagret. Detta medför även ett mer optimerat trafikflöde i nätverket. Vidare föreslås att routingprotokollet OSPF implementeras med fyra areor

  • 2037.
    Åkesson, Tom
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för naturvetenskap, lantmäteri- och maskinteknik.
    Fransson, Mårten
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för naturvetenskap, lantmäteri- och maskinteknik.
    Avvägning och trigonometrisk höjdmätning kontra satellitbaserad höjdmätning: En jämförelsestudie2014Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Eftersom nästan allt i vårt samhälle kan knytas till en geografisk plats måste det finnas kartor så att vi kan orientera oss och ta beslut. Inom lantmäteriet, som har det övergripande ansvaret för kartor i Sverige, redovisas de flesta objekt med plana koordinater. För koordinatbestämning i plan är mätosäkerheten låg även med nya satellitbaserade metoder. Vid höjdmätning, som blir allt mer viktig, är den teoretiska mätosäkerheten högre. Därför är syftet att undersöka, genom en kvantitativ studie, om satellitbaserade metoder kan ersätta avvägning och trigonometrisk höjdmätning fullt ut. För att uppfylla syftet har studien en utgångspunkt i tre frågeställningar.

    Vilken avvikelse som finns mellan avvägning och trigonometrisk höjdmätning, NRTK och efter beräknad statisk mätning är den stora frågan som ligger till grund för diskussionen.

    Studien visade att avvikelsen från det avvägda värdet var minst för trigonometrisk mätning

    följt av NRTK. Efterberäknad statisk mätning har en större avvikelse. Avvikelsen kan också benämnas för mätosäkerheten vilken, i studien, jämförs med de krav på toleranser som finns inom byggsektorn och vid fastighetsbildning. Jämförelsen svarar på den andra frågan.

    För att besvara den tredje frågeställningen valdes att mäta tidsåtgången och ställa medelvärdena, för respektive metod, mot varandra vilket visade att de satellitbaserade metoderna är mer tidseffektiva utifrån etablering av instrument. Den statiska bärvågsmätningen gör sig inte rättvis i resonemanget eftersom mätresultatets noggrannhet är beroende av tiden mottagaren samlar satellitdata.

    Efter en reflektion av metoden drogs en slutsats att initialpunktens förhållande till vegetation och även enstaka bebyggelse påverkade mätresultatet för den statiska bärvågsmätningen negativt 

  • 2038.
    Åstrand, Erik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    A Framework for optimised welding of fatigue loaded structures: Applied to gas metal arc welding of fillet welds2016Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Welding is a key process for heavy steel structures, but it is also a weak link in the structure since fatigue fractures in welds are a common cause of failure. This thesis proposes several changes in order to improve the fatigue properties in acost effective way, enabling reduced weight and reduced cost of welded structures. The main idea is to adapt the weld requirements and welding procedures to the load conditions of the weld. This approach ensures that the main focus in the welding process is the critical characteristics of the welds fatigue life properties. The fatigue life critical properties are most often related to the geometrical factors of the weld such as the radius at the weld toe or the penetration in the root. The thesis describes a holistic view of the subject and covers fatigue, weld quality, weld requirements and welding procedures. It becomes evident that the traditional way of working without a direct connection to fatigue is not the best. With an adaptation to the load conditions and fatigue, it is possible to enhance the fatigue life and reduce the welding cost. The main challenge is to connect the welding process, weld requirements and fatigue life properties. It is needed for an optimised welding process of heavy structures subjected to fatigue and toget a predictable fatigue life. Welds optimised for enhanced fatigue life properties are not necessary accepted according to the requirements in a current standard. Several welding procedures are proposed for improving the fatigue life properties of the weld, which indicate a high potential for enhanced fatigue lifeof fillet welds. The idea is to replace the "standard" fillet weld with three different weld types: (i) Welds with deep penetration, (ii) Welds with large weld toe radius and (iii) Welds produced with low cost. Together with customised requirements and reduced over-welding there is a vast potential for reduced weight, reduced cost and increased productivity.The main contribution of this thesis work is the cross-functional studies including design, analysis, production and quality control. This gives a framework for improvements supporting reduced cost and reduced weight of VIII welded structures without reducing the fatigue strength. Many shortcomings have been highlighted to change the welding from a state where welds are done in a way as they "always" have, by tradition, to a more contemporary situation where weld requirements and welding procedures are actively chosen to match the load conditions of the weld. This result in requirements and welding procedures which actually are connected to the fatigue properties as defined by the loading conditions, and where auditors with high probability can say that an accepted weld actually is better than a rejected weld.

    Fulltekst (pdf)
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    Fulltekst (pdf)
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  • 2039.
    Åstrand, Erik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd Forskningsmiljön industriprocesser. Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW). Volvo Construction Equipment, Carl Lihnells väg, Braås, Sweden .
    A new innovative toolbox for lean welding of fatigue loaded structures2015Inngår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 81, nr 1-4, s. 635-643Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Welding is a key manufacturing technology in the production of heavy steel structures, but it is likewise a weak link in the production chain since fatigue fractures in welds is a common cause of failures. This paper proposes several changes in the process to make the manufacturing more efficient and to improve the fatigue properties. The idea is to adopt the weld quality demands for the purpose of the weld and to connect them to the welding procedures. This approach ensures that the primary focus during welding is at the critical characteristics which add value to the welded structure through an enhanced fatigue life. These fatigue life-critical properties have been found to be related to the local weld geometry in the weld toe and at the weld root. Traditional demands related to the good workmanship of welding can often be neglected, due to its limited effect to the fatigue life. The research presented in this paper has contributed to the development of welding procedures for improved fatigue life properties at the critical points of the weld. Results indicate a considerable potential for enhanced fatigue life of fillet welds. The idea is to replace the standard fillet welds with a new toolbox containing three different welds: (i) welds with optimized penetration, (ii) welds with optimized weld toe, and (iii) welds with a low cost. Right usage of these weld types contributes to an efficient production that offer a long fatigue life. This paper describes a holistic view of the subject and highlights issues with the traditional way of working. The challenge and the novelty in the paper are the connection between the welding process, weld demands, and fatigue life properties. This connection is necessary for the development of welding procedures that can contribute to the fabrication of weight optimized welded structures with a predictable life. © 2015 Springer-Verlag London

  • 2040.
    Åstrand, Erik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd Forskningsmiljön industriprocesser.
    Key Changes in the Welding of Fatigue Loaded Structures2014Inngår i: Proceedings of the 6th International Swedish Production Symposium 2014 / [ed] Stahre, Johan, Johansson, Björn & Björkman, Mats, 2014, s. 1-7Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper discusses welding problems of today and the possibilities for tomorrow for companies in the welding industry. By leaving old welding procedures based on traditions and applying new scientifically developed welding demands and procedures there is a vast potential to improve strength performance of the structures and increased competitiveness regarding weld work for the companies. Unfortunately, no changes are done easily and quickly and this paper gives proposals how changes can be done efficiently.

  • 2041.
    Åstrand, Erik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    The Ad Hoc Nature of Weld Quality and Welding Procedures for Fatigue2013Inngår i: Design, Fabrication and Economy of Metal Structures: International Conference Proceedings 2013, Miskolc, Hungary, April 24-26, 2013 / [ed] Jármai, Károly, Farkas, József (Eds.), Berlin: Springer, 2013, s. 243-248Konferansepaper (Fagfellevurdert)
  • 2042.
    Åstrand, Erik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd Forskningsmiljön industriprocesser.
    Weld Procedures and Demands for Improved Fatigue Strength of Single Load Carrying Fillet Welds2013Inngår i: Trends in Welding Research: Proceedings of the 9th International Conference / [ed] T. DeRoy, S.A. David, T. Koseki, H. Basdeshia, Chicago: ASM International, 2013, s. 798-804Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Traditional weld demands on throat size and leg length does not support a welding process for improved penetration. This paper includes theoretical analysis of welded samples showing the potential with welds that have a prescribed asymmetry. Weld with a larger leg length against the web plate offer in this study improved fatigue properties and could also offer potential for reduced welding time, a smaller amount of filler material and potentially make the quality inspection more relevant. Copyright © 2013 ASM International® All rights reserved.

  • 2043.
    Åstrand, Erik
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Bolmsjö, Gunnar
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Sikström, Fredrik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för automationssystem.
    Lindgren, Eric
    Improved fatigue properties of welded box beams by tailored welding procedures for high penetration fillet weldsInngår i: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024Artikkel i tidsskrift (Annet vitenskapelig)
  • 2044.
    Åstrand, Erik
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW). Volvo Construction Equipment AB, Braås, Sweden .
    Stenberg, T.
    Royal Institute of Technology (KTH), Department of Aeronautical and Vehicle Engineering, Division of Lightweight Structures, Stockholm, Sweden .
    Jonsson, B.
    Volvo Construction Equipment AB, Braås, Sweden .
    Barsoum, Z.
    Royal Institute of Technology (KTH), Department of Aeronautical and Vehicle Engineering, Division of Lightweight Structures, Stockholm, Sweden .
    Welding procedures for fatigue life improvement of the weld toe2016Inngår i: Welding in the World, ISSN 0043-2288, E-ISSN 1878-6669, Vol. 60, nr 3, s. 573-580Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the results of an experimental study of gas metal arc welded, GMAW, cruciform joints made of common construction steel S355. The hypothesis is that smooth undercuts in as welded conditions can give enhanced fatigue properties similarly as post treated welds. Undercuts are generally seen as a defect or imperfection. Welders try to avoid these and repair them when they occur, which result in increased production lead time. Post weld improvement methods i.e. grinding or high-frequency-impact treatment (HFMI) as fatigue-enhancing post-treatment methods enforce amongst other effects a certain smooth undercut-shaped groove in the treated weld toe region. The obtained shallower weld toe transition reduces the geometrical notch effect and increases fatigue strength. This paper presents a study whereas welded specimens with a weld toe geometry similar to what is obtained by weld toe grinding or HFMI-treatment, has been produced, fatigue tested and analyzed. The improvement of the fatigue strength is comparable to post-weld treated specimens. It has proven to be an efficient way to achieve high-quality welds without introducing any additional operations in production, thus enabling weight reduction using cost-effective methods.

  • 2045.
    Åström, Hans
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Stenbacka, Nils
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd Forskningsmiljön industriprocesser.
    Hurtig, Kjell
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för tillverkningsprocesser.
    Arc Efficiency for Gas Tungsten Arc Welding DCEN-GTAW2013Konferansepaper (Fagfellevurdert)
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    fulltext
  • 2046.
    Öberg, Anna Ericson
    et al.
    Volvo Construction Equipment, Arvika, Sweden.
    Sikström, Fredrik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).
    Barriers for industrial implementation of in-process monitoring of weld penetration for quality control2017Inngår i: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 91, nr 5-8, s. 2427-2434Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The research conducted sheds a light on the question why robust in-process monitoring and adaptive control are not fully implemented in the welding industry. In the research project FaRoMonitA, the possibilities to monitor the weld quality during welding have been investigated. Research conducted in this area has merely focused on technical issues investigated in a laboratory environment. To advance the research front and release some barriers related to industrial acceptance, the studies conducted in this paper have been both quantitative and qualitative in form of experiments combined with an interview study. The quality property weld penetration depth was chosen for in-process monitoring to evaluate the industrial relevance and applicability. A guaranteed weld penetration depth is critical for companies producing parts influenced by fatigue. The parts studied were fillet welds produced by gas metal arc welding. The experiments show that there is a relationship between final penetration depth and monitored arc voltage signals and images captured by CMOS vision and infrared cameras during welding. There are still technical issues to be solved to reach a robust solution. The interview study indicates that soft issues, like competence and financial aspects, are just as critical.

  • 2047.
    Öberg, Anna
    et al.
    Volvo.
    Hammersberg, Peter
    Chalmers, Material- och Tillverkningsteknik.
    Svensson, Lars-Erik
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för industriell produktion.
    Selection of Evaluation Methods for New Weld Demands: Pitfalls and Possible Solutions2012Inngår i: NDT in Service of Society, in Safety Assurance, Quality Control and Condition Monitoring: The 18th World Conference on Nondestructive Testing, WCNDT-2012 / [ed] M. Johannes, AOSIS, 2012, s. 1-10Konferansepaper (Fagfellevurdert)
    Abstract [en]

    New demands often create a need for new evaluation methods. However, there are several pitfalls when choosing those methods that can endanger the expected benefits.

    This study shows examples from the implementation of a new welding standard at several sites in the same company. It focuses on possible pitfalls as well as probable causes and potential solutions with a push- and pull-approach. The examples cover the problems with unclear or too simplified demands, lack of evaluation method and incapable evaluation methods.

    The ability to handle and prevent the described issues is a prerequisite in order to be able to develop the organisation in means of quality assurance for light weight structures.

  • 2048.
    Örnskär, Rasmus
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avd för naturvetenskap, lantmäteri- och maskinteknik.
    Förbättrings och layout förslag för pakethanteringen hos SKF Logistics Services Sweden2014Independent thesis Basic level (professional degree), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Det förväntade resultatet av denna tes är att kartlägga processen innefattande den manuella hanteringen av packet hos SKF Logistics Services Sweden. Förslag på förändring av processen och layout förslag skall tas fram av författaren. Dessa förslag grundar sig inom lean och ergonomi för att hitta förbättringar i processen och förbättra den nuvarande arbetsmiljön som idag innefattar mycket tunga lyft för personal.

    Om förslagen implementeras kommer detta ge ett förbättrat flöde. Ergonomi kommer även att förbättras genom att tunga lyft kommer att minimeras. Även att bygga om arbetsstationerna med de ergonomiska modellerna från arbetsmiljöverket kommer att förbättra arbetsmiljön för personal i processen. Vissa förslag som ges i denna tes är inte helt förankrade i organisationen men är medtagna för att visa på de stora besparingar och eliminering av icke värdeskapande aktiviteter som kan göras om kringliggande processer förändras. Detta kommer påverka fler avdelningar än SKF Logistics Services Sweden och mer förarbete måste genomföras för att dessa förslag kan genomföras

  • 2049.
    Örtendahl, Niklas
    Högskolan Väst, Institutionen för ingenjörsvetenskap.
    En studie på emballeringssystem ur ett resursoptimeringsperspektiv2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [sv]

    Dagens industri omfattas av hård konkurrens som kräver ständig verksamhetsutveckling samt en kontinuerlig ökning i produktvariation för att möta kunders krav. Managementverktyg såsom Lean production som fokuserar på en kontinuerlig reducering av slöseri i verksamheters samtliga delar spelar en nyckelroll i dagens industriella företagsvärld. I syfte att förena ständiga förbättringar med organisationens välmående krävs strukturerade tillvägagångssätt i form av väl ordnade förbättringsarbeten. Arbetet som utförts på Swegon AB i Kvänum identifierar möjliga förändringar kring emballeringsprocessen i effektiviserings och resursbesparingssyfte. Företaget producerar luftbehandlingsaggregat och fläktar för inomhusanvändning. Produkterna återfinns bland annat i arenor, hotell, sjukhus, flygplatser, universitet samt bostäder.  Dagens emballeringsprocess upplevs som ineffektiv. Företaget ser förbättringspotential i transportnedskärning, minimering av fysiska och affärsmässiga hanteringssteg och ett därmed minskat behov av lagringsytor och buffertar. I samband med en ombyggnation som framför allt berör materialflöden och layouter, struktureras stora delar av produktionen stegvis om, från en funktionsorienterad till en i allt större utsträckning processorienterad layout. Om förändringsförslagen skall implementeras sker detta troligtvis i samband med denna ombyggnation. Arbetet initierades genom en omfattande kartläggning av dagens emballeringsprocess. Genom intervjuer, observationer samt upprättandet en processkarta påbörjades empiriinsamlingen. Kartläggningen avslutades genom tillämpningen av bland annat fiskbensdiagram, där grundorsaker till identifierade problem strukturerades. Kontinuerliga litteraturstudier genomfördes i syfte att styrka de i arbetet tillämpade metoderna. Teorin behandlar främst Lean production med fokus på slöseri och standardiserade arbetssätt. Förändringsförslag genererades löpande i nära samarbete med främst tekniker och produktionspersonal. Fokus lades på att reducera de icke värdeskapande momenten inom processen. Arbetet resulterar i fyra olika förändringsförslag: skanning, layoutförändringar och kittning. Dessa ger upphov till ett minskat resursbehov samt ökad kvalitet mot kund. Dessutom medför förslagen förbättrade möjligheter till en standardisering av processen.  

  • 2050.
    Östling, Dan
    et al.
    Sandvik Teeness AS, Ranheimsveien 127, Trondheim, Norway.
    Magnevall, Martin
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Sandvik Coromant AB, Sandviken, Sweden.
    Modelling and characterization of nonlinearities in a tuned mass damper-impulse hammer versus shaker excitation2016Inngår i: Proceedings of ISMA 2016 - International Conference on Noise and Vibration Engineering and USD2016 - International Conference on Uncertainty in Structural Dynamics / [ed] Sas P.,Moens D.,van de Walle A., KU Leuven, Departement Werktuigkunde , 2016, s. 3711-3719Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The rubber springs of a tuned mass damper (TMD) exhibit both nonlinear stiffness and damping, which complicates measurements of the frequency response function (FRF) of the device. In this paper we model and compare the frequency responses measured with both impulse hammer excitation and a shaker base excitation method. Since the impulse response will spend only a short time in the nonlinear regime, a reasonable assumption is that the nonlinearities will be less apparent and more difficult to determine. The results show that this is not the case and that both methods yield similar nonlinear parameters. By comparing responses at different excitation levels with appropriate nonlinear models, the nonlinearities can be determined. The results indicate that these approximations of the nonlinear effects are able to describe the dynamic behaviour of the TMD, and that the nonlinear properties of the material differ somewhat in the two measurement situations.

38394041 2001 - 2050 of 2050
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