Coupling analysis of mechanism fatigue wear in vibration-thermal environment

The aircraft drag-parachute mechanism is key to ensuring the smooth deployment of the parachute. It is of great significance to study its damage evolution for aircraft landing safety. To simulate the time-varying damage of this mechanism under a vibration-thermal environment, a modeling method is proposed. The method considers the coupling between fatigue damage and fretting wear and introduces the local friction temperature rise on the contact surface of the study object. The influence of the two phenomena, the morphologic evolution of the contact surface with different slip types, and the problem of motion stuck are studied. The results show that, when considering the coupling influences of friction temperature increase and fatigue damage on wear, the friction force in the case of gross slip is mostly unchanged, whereas that in the case of partial slip increases significantly. In the second case, compared with the calculation of friction force that ignores the influences of both phenomena, when considering the coupling influence of friction temperature increase or fatigue damage on wear, the friction force on the contact surface increases by approximately 6.7 %. However, when considering the combined coupling influence, it increases by approximately 20 %. Therefore, omitting the combined coupling influence reduces the prediction result of mechanism stuck failure probability smaller.