Fatigue Life Prediction of Annular Thermoelectric Generators Under Thermal Cycling Load

Under time-varying loads, thermoelectric devices are prone to failure due to fatigue accumulation. The fatigue life of annular thermoelectric generators (ATEGs) has not yet been studied. The primary goal of this paper is to numerically investigate the fracture parameters and fatigue life of ATEG legs with central cracks. When there are central circumferential and radial cracks, the effects of temperature difference on the stress intensity factor (SIF) at the crack tip and fatigue life of the ATEG are investigated in the case of specific geometry. The results show that, in the temperature range 300–550 K, while the SIF at the fracture tip increases as the temperature difference increases, none of its values exceed the critical SIF, which prevents crack propagation. Nonetheless, the thermal cycling load can cause fatigue fracture and crack propagation in the legs, and a greater temperature difference shortens the service life of the ATEG. Furthermore, when the temperature difference is 50 K, the ATEG with a central radial crack have an 18.7% longer lifetime than the ATEG with a central circumferential crack. The findings will provide a theoretical foundation and recommendations for long-term reliable application of ATEGs in waste heat recovery.