Research on Stress Relaxation Life Prediction and Micro-Mechanism of Push Rod Spring

As the number of spacecraft docking operations and service duration increases, the stress relaxation phenomenon in push rod springs can significantly affect the reliability of the docking and separation processes. Therefore, the study of push rod spring stress relaxation is very important for the docking and separation of spacecraft. In this study, accelerated experiments were conducted to investigate the stress relaxation of push rod springs. Stress relaxation data for push rod springs at different temperatures were obtained. Then based on the thermal activation theory and the Arrhenius model, the service life of push rod springs under actual working conditions was predicted. Subsequently, transmission electron microscopy (TEM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) experiments were conducted on the push rod springs to investigate the micro-mechanism of stress relaxation. The results indicate that under room temperature conditions, the service life of the push rod spring, with a load loss rate of 10%, is 4.9 years. Additionally, the mechanism of stress relaxation failure in push rod springs is attributed to the accumulation of minor plastic deformation over time, caused by the dislocation slip within the spring material.