Microstructure-based computational fatigue life prediction of polycrystalline alloys

icaf2023 Tracking Number 30

icaf2023 presentation

In this research microstructure-based fatigue modeling is conducted to predict the low cycle fatigue (LCF) crack nucleation life of a nickel-based alloy, Haynes 282. A three-dimensional representative volume element (RVE) consisting of polycrystalline aggregate is constructed for the material using Voronoi tessellation with the grain size distribution from the real material and grain orientations randomly assigned for isotropy. Hill’s yield criteria and linear strain hardening are employed to describe the anisotropic plasticity of each grain, using the finite element method (FEM), such that the overall deformation response matches the cyclic hysteresis behaviour of Haynes 282 alloy at the macroscopic scale,. The fatigue crack nucleation life of Haynes 282 alloy is predicted using the Tanaka Mura Wu (TMW) model based on the material surface energy, shear modulus, Burgers vector, and the plastic strain range at the microstructural level. The fatigue crack growth life under LCF conditions is described using the Tomkins equation. It is demonstrated that this approach can computationally predict the fatigue life of Haynes 282 alloy and estimate the scattering of the fatigue life by the simulations with different sets of the grain distribution functions. The model predictions are in good agreement with the coupon tests, in a statistical sense. Furthermore, the effect of grain orientation on the fatigue crack nucleation is discussed.