Computational modelling of transversely isotropic high-cycle fatigue using a continuum based model

In this paper a computational implementation of a continuum based transversely isotropic high-cycle fatigue model is described. The key idea of that model is the moving endurance surface where the movement is described by a back stress type tensor, the evolution of which is described by a rate type equation. Furthermore, damage accumulation is also governed by a rate type evolution equation. The endurance surface is given in terms of invariants from the integrity basis of the transversely isotropic symmetry group. The key point of the formulation is the additive split of the stress tensor in two components; one in the transverse isotropic plane and another in the longitudinal direction. The material parameters are calibrated for the forged 34CrMo6 steel and for the isotropic AISI-SAE 4340 steel. The model is implemented in the Abaqus FE-program using the user material subroutine.