Failure analyses for plate monotonic/cyclic and elbow out-of-plane cyclic loading tests using the Gurson–Tvergaard–Needleman model

In this study, an analytical approach is proposed to simulate the failure behavior of a thinned-wall pipe elbow subjected to internal pressure and out-of-plane cyclic bending loads. This approach incorporates the Gurson–Tvergaard–Needleman model, whose parameters were determined by the plate monotonic tensile test and finite element analyses. The applicability of this analytical approach for low-cycle fatigue failure was confirmed through experiments and simulations. The analytical results captured the failure behavior of the pipe elbow during the out-of-plane cyclic bending test. This finding suggests that the analytical approach can be used for nonlinear deformation evaluation and multiaxial low-cycle fatigue assessment of piping systems. • Analytical approaches for monotonic and cyclic loading tests include the GTN model. • True stress–true strain relationship considering softening effects is well determined. • DIC technique improves strain measurements after necking and buckling deformations. • Applicability of analytical approach for low-cycle fatigue is confirmed. • Analytical approach captures multiaxial low-cycle fatigue failure of the pipe elbow.