GEOMETRY EFFECT OF WELDED-JOINTS ON FAILURE ASSESSMENT CURVES

In the present work effect of weld width parameter, h/c, on the J-inte gral and the failure assessment diagram (FAD) has been investigated. T he FAD in this studies is based on the CEGB/R6 procedure option 3. In the investigation center-cracked tensile specimens with mismatched wel ds 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 fac tor, M, was selected to be 0.8, 1.0 and 1.2. The base material investi gated was A508C13 steel. Numerical computation was performed using an ABAQUS two-dimensional elastic-plastic finite element analysis code. T he results have indicated that the weld width parameter has evident in fluence on the J-integral and the FAD in the elastic-plastic loading c ondition. With the increase in the weld width parameter, the J-integra l of undermatched joints are increased, while the J-integral of overma tched joints are decreased. In the meantime, with the increase of h/c, the safety region of the FAD is reduced for the undermatched joints a nd expanded for the overmatched joints. Moreover, the results display the effects of strength mismatch and crack depth on the FAD. The safet y zone of the FAD clearly expands for the overmatched joints and contr acts for the undermatched joints. No matter what mismatched joints or homogeneous materials, the safety margin of the FAD is expanded for th e specimens with deep crack. Thus, the weld geometry should be conside red, when one aims to construct the expression of J-integral estimatio n or to carry out the integrity assessment of welded structures using the FAD. (C) 1998 Elsevier Science Ltd.