Random fatigue life prediction of metallic thin-walled structures under thermo-acoustic excitation

Metallic thin-walled structures subjected to thermal-acoustic loadings will exhibit complex nonlinear response. Based on the nonlinear thermal-acoustic response analysis, the rain flow cycle counting (RFC) method was used to calculate the number of fatigue cycles. Then the Miner accumulative damage model was employed in conjunction with various mean stress models, including Morrow TFS and SWT, to predict the high cycle fatigue life. The nonlinear responses of 2024-T3 aluminum plate were obtained under band-limited Gaussian white noise loadings with pre/post-buckled temperature loadings, and the fatigue life was estimated. Analytical results show that the fatigue life of pre-buckled plate decreases with the increase of temperature, keeps going down to the lowest and undergoing persistent snap-through at the post-buckled region, and then goes up after entering intermittent snap-through region, which indicate that there exists a specific relationship between the thermal-acoustic fatigue life and nonlinear response behaviors.