Cyclic elastoplastic responses of thick-walled FG pipe behaves as a power law function considering damage evolution

Abstract

The present article is devoted to the cyclic responses of functionally graded (FG) pipe incorporating continuum damage mechanics parameters under thermomechanical loadings. The thermal, mechanical, the coefficients of Chaboche nonlinear kinematic hardening model, and damage parameters are considered to be varied continuously in the radial direction with power-law function, instead of being constant. The implicit backward Euler integration scheme along with return mapping algorithm implemented within user-defined material subroutine (UMAT) in the ABAQUS finite element (FE) software obtain the numerical solutions. The accuracy of the numerical algorithm in predicting the cyclic responses of metals is validated through comparing with experiments performed by Hassan and Kyriakides and also FE simulation. The sensitivities of damage values to the FG power-law index corresponds to damage parameters and shell thickness are investigated. Finally, the influences of damage evolution on the cyclic elastic-plastic behaviors of FG pipe under different combinations of thermomechanical loadings through Bree’s diagram are carefully explored.