Assessment of Cyclic Plasticity Behaviour of Primary Piping Material of Indian PHWRs Under Multiaxial Loading Scenario

The present study is aimed at assessment of stabilized cyclic elastic–plastic stress/strain response of low C–Mn steel used as the primary piping material of Indian PHWRs. The material model considers von Mises yield criterion, three decomposed non-linear kinematic hardening-based Chaboche model and associative flow rule. Three-dimensional tubular geometry (as tested) has been analysed using in-house developed finite element code. The Chaboche’s parameters have been calibrated using the stabilized low-cycle fatigue test loop for a given pure axial strain amplitude. These calibrated parameters have been used to predict cyclic plastic material response for pure axial, pure torsion, in-phase axial–torsion and out-of-phase axial–torsion strain paths. The predicted cyclic stress–strain response under pure axial, pure torsion and in-phase axial–torsion conditions is nearly comparable to test response. However, the material stress response is underestimated in axial and shear directions for non-proportional axial–torsion conditions.