This document presents the DNV Platform of Computational Welding Mechanics, CWM, with its associated CWM-methodology. That has been developed, validated and implemented as a part of DNV’s Technology Leadership program in the field of Structural Integrity and Materials Technology.A successful CWM implementation requires that the actual organisation has gained the knowledge and understanding of the following related topics:

- Welding Engineering with an emphasis on the welding process and its thermodynamics

- Weld process quality control such as calibration, validation as well as DAQ, (Data Acquisition)

- Transient thermo-mechanical coupled FE-analyses and constitutive modelling

- Computational platforms comprising the selection of hardware, operative system and FEM-code as well as suitable pre- and post-processing tools

From that perspective there is a lack of reliable and/or hands-on oriented CWM Engineering Handbooks and best recommended practices available on the market. For that sake is the DNV CWM-methodology and its hands on solutions presented.

The CWM-methodology described can not only be used for residual stress assessments, as presented in this report. It can also be used for various applications such as assessment of used and/or proposed WPS, Welding Procedure Specifications as well as optimisation of the manufacturing and production process of integrated metallic structures.

From the results of a parametric CWM-study have three (3) factors been identified to drive and/or contribute to the magnitude of the weld residual stresses in ship steel plate materials. The contributing and/or driving factors identified are the

:- Thermal- and Mechanical Boundary Conditions during the production welding

- Yield stress difference between the base- and the weld filler material

- Weld heat input, Q, which affects the weld cooling time