Geometry effect of welded joints on failure assessment curves

Abstract

Abstract In the present work effect of weld width parameter, h c , on the J -integral and the failure assessment diagram (FAD) has been investigated. The FAD in this studies is based on the CEGB R6 procedure option 3. In the investigation center-cracked tensile specimens with mismatched welds were used. Crack size parameter, a W , was equal to 0.1 and 0.5. The values of h c was changed from 0.1 to 0.5. Weld strength mismatch factor, M , was selected to be 0.8, 1.0 and 1.2. The base material investigated was A508C13 steel. Numerical computation was performed using an ABAQUS two-dimensional elastic-plastic finite element analysis code. The results have indicated that the weld width parameter has evident influence on the J -integral and the FAD in the elastic-plastic loading condition. With the increase in the weld width parameter, the J -integral of undermatched joints are increased, while the J -integral of overmatched joints are decreased. In the meantime, with the increase of h c , the safety region of the FAD is reduced for the undermatched joints and expanded for the overmatched joints. Moreover, the results display the effects of strength mismatch and crack depth on the FAD. The safety zone of the FAD clearly expands for the overmatched joints and contracts for the undermatched joints. No matter what mismatched joints or homogeneous materials, the safety margin of the FAD is expanded for the specimens with deep crack. Thus, the weld geometry should be considered, when one aims to construct the expression of J -integral estimation or to carry out the integrity assessment of welded structures using the FAD.