A novel thermo-mechanical local damage model for quasi-brittle fracture analysis

Abstract

This paper is devoted to numerical investigation of quasi-brittle fracture under thermal-elastic loading condition using a novel thermal-mechanical local damage model associated with the enhanced bi-energy norm based equivalent strain. In contrast to the non-local or gradient-enhanced damage models, a local damage counterpart generally requires less computational effort. The common mesh-dependent issue encountered in the local approaches is here mitigated by incorporation of fracture energy and element characteristic length into the calculation of damage evolution. Equivalent strain is derived based on the so-called bi-energy norm concept and the recent Mazars’ criterion. Here, the damage evolution is induced by both the mechanical and thermal loads, in which both stress and thermal conductance capacity are reduced across the damage zone. In this work, we present an efficient staggered scheme to solve the coupled thermal-mechanical damage equations. The performance and accuracy of the developed model are validated via several numerical examples of quasi-static crack growth problems, in which comparisons between the computed results and reference solutions from other numerical approaches and/or experiments are presented.