Benchmarks for finite element analysis of creep continuum damage mechanics

Creep rupture life can be predicted using a continuum damage mechanics approach incorporated within a finite element (FE) formulation. The rate of change of a damage parameter, ω, ranging from ω=0 (no damage) to ω=1 (100% damage), is computed within each element, until failure occurs in the material cross-section. The main difficulty in the numerical formulation arises due to the very small time steps needed as the damage parameter increases to 1. This paper presents the results of a number of benchmark tests involving the FE analysis of creep continuum damage mechanics that can be used to verify the FE solutions. Two independent FE codes are used; an in-house code (FE-DAMAGE) and a commercial code (ABAQUS) in which a user-subroutine (UMAT) is incorporated. The results of a series of tests used to represent uniaxial, biaxial, triaxial and multi-material creep and damage behaviour are presented.