Analysis of Vibration Characteristics and Fatigue Life Prediction of Thin-Walled Connection Structures

To explore the structural strength of thin-walled joint structures in the combined power nozzle of high-speed vehicles under coupled thermal-acoustic-vibration multi-physics loading, this study conducted an analysis of vibration characteristics and a prediction of fatigue life. Focusing on a representative plate-beam bolted joint structural unit, the modeling, computation, and analysis of the structure’s vibration behaviors under thermal-acoustic-vibration loading were implemented by means of the coupled Finite Element Method/Boundary Element Method (Coupled FEM/BEM). The improved rainflow counting method was applied to quantify the time-domain vibration stress responses; a corresponding rainflow damage matrix was then established, and the structural fatigue life was predicted based on this framework.