A Research on Damage Mechanics of Dynamic Reliability

By taking the axial tension member as an example, the damage caused by the cyclic stress influencing reliability was researched. According to the damage mechanics theory, some micro-cracks were observed in the material with cyclic load. With the increase of times loads inflicting, the fresh micro-cracks were formed; meanwhile, the existing cracks further extended, consequently, the effective bearing area reduced and the effective stress increased. By using the model of stress-strength interference, ignoring the effects of erosion and aging on the strength degradation, effective stress increasing lead by the change of damage were only taken into account. This research took the intensity as a random variable and view stress as a random variable which changed with the times of loading, and combined physical experiments and simulation of sampling. Furthermore, the dynamic reliability curve of the stress of tension member that changes with the loading times was simulated; the changing trends of dynamic reliability under different cyclic loading at the same temperature and the same cyclic loading at different temperatures were analyzed respectively. The results suggested that the reliability presents a downward trend when the life is about 80 %, the dynamic reliability curve shows a typical bathtub curve in the later two steps. Copyright © 2014 IFSA Publishing, S. L.