Thermal fatigue behaviors of thin-walled structures with holes: Experiments and phase field fracture modeling

Abstract

The assessment of thermal fatigue behaviors of thin-walled structures with holes is a challenging task. A novel experimental approach was designed to test the thermal fatigue behaviors of thin-walled structures with holes. The experiments were conducted under three test conditions (300–850/950/1000 ℃) to investigate the behaviors of crack initiation and early propagation. The cyclic temperature loading exhibits high-transient and wide-ranging characteristics, enabling the construction of a non-uniform transient temperature field in the heating step. A thermal fatigue phase field model was developed for elastoplastic solids, and thermal fatigue fracture modeling and life prediction were performed. The phase field effectively reproduces crack morphology, and the experimental results closely match the simulation results when fatigue parameters are properly selected. Raising the upper limit of temperature will significantly diminish thermal fatigue life, accelerate crack growth, and induce a broader range of material damage. The temperature gradient in the heating step enhances the cyclic plastic behavior at the edge of the hole, significantly amplifying the detrimental impact of thermal fatigue.