Modelling of creep-damage in thick plate subjected to thermo-mechanical loading cycles

This paper is an extension of the previous authors' papers dealing with the formulation of coupled thermo-creep-damage in 3D rotationally-symmetric structures in the case of combined reverse cyclic mechanical and thermal loads. The thermo-damage coupling is described by the modified Fourier heat flux equation, where the second-rank tensor of thermal conductivity with the damage tensor as an argument is defined. The crack closure/opening effect is incorporated by new effective stress definitions for tension or compression in constitutive equations. It allows for description of incomplete damage deactivation on reverse loading cycles by a new diagonal crack-closure second-rank tensor. Damage evolution is governed by the mixed isotropic/anisotropic Murakami model, modified in order to eliminate non-uniqueness in description of damage growth in the case of rotational symmetry. The creep process coupled with damage is controlled by the Murakami-type equation adapted to reverse cyclic loads. The damage analysis in a 3D plate under thermo-mechanical loadings, which consists in a simultaneous non-homogeneous temperature distribution in the plate over the upper plate originated from the point heat source positioned over the upper plate surface, and the uniform reverse cyclic pressure, is presented as an example.