Influence of weld material properties on fracture mechanics parameters in welds analysed by FE calculations

The mechanical behaviour of welds is characterized by the properties of the base material (BM), the weld material (WM) and the heat affected zone (HAZ). This has to be considered when usual concepts of strength assessment developed for structures of a single material shall be applied to structures with welds. In an earlier paper of the authors the scope of applicability of the various elastic-plastic fracture mechanics concepts to welds based on various two-dimensional elastic-plastic finite element (FE) calculations for a CT-100 specimen with a welded joint in the ligament region, of base material properties only, of welding simulated material properties only and of weld material properties only has been discussed ( Müller, Veith 1985 ). The objective of this paper is to contribute to the discussion on the influence of weld material properties on the fracture mechanics parameters of a weld in the elastic-plastic regime. Two WMs of different yield strength levels are regarded, one close to but below the yield strength of the HAZ region near the fusion line called WM1 and the other one close to but above the yield strength of the BM called WM2. Additionally, various one material models of WM, HAZ and BM properties are analysed for comparison.