Nonlinear Finite Element Analysis of a Full-Scale Test of a Cracked Dissimilar Weld for Ageing Nuclear Power Piping and Failure Assessment

In this paper, non-linear finite element analysis of a full-scale laboratory test, a Benchmark four-point bending test of a straight pipe with an obliquely inserted crack in a dissimilar metal weld of ferritic steel (A508), austenitic steel (316L), weld material (308L) and buttering material (309L/308L), is conducted. The behavior of the crack front at the load level, at which the crack initiation is observed in the test, are computed, summarized and examined. A comparison to the results from the test and from linear finite element analysis is made. Computed results confirm our recent observations through linear fracture mechanics assessment: (i) The fracture initiation predicted by using J-integral based mixed mode cracking criteria may approximately be achieved by an “effective stress intensity factor” based approach; (ii) it is not conservative to use a purely mode-I based criterion for the fracture assessment for typical problems of mixed mode driven cracking. This paper is an extension of our recent work reported in the 2015 PVP conference, which addresses the fracture assessment using linear finite element analyses.