2008 Volume 26 Issue 2 Pages 145-151
A welding distortion prediction method based on inherent strain concept was presented. In the proposed method, welding distortion of large welded structures could be estimated by elastic analysis using the result of thermal-elastic-plastic analysis result of smaller welded joints or components. Thermal-elastic-plastic analysis is performed to calculate residual plastic strain distribution, which is the input data for the elastic analysis of welding distortion. The obtained residual plastic strain distribution is mapped to non-deformed finite element models to calculate welding distortion by elastic analysis. The mapping procedure is done in different ways for welding start/end parts and the rest of weld length in order to take into consideration of unsteady strain distribution at start/end of welds. For start/end parts, strain distribution used is identical with thermal-elastic-plastic analysis. For the part except start/end parts, strain distribution obtained by thermal-elastic-plastic analysis is extracted from the center of weld length and is extruded along welding direction.
The proposed method was applied to the welding distortion prediction of joints with weld length 900 mm and 1200 mm based on thermal-elastic-plastic analysis result of a joint with weld length 600 mm. The estimated results were in good agreement with the thermal-elastic-plastic analysis results of models of corresponding weld length to show the validity of the proposed method.