Abstract：The fatigue reliability of space structures composed of thin-walled tube element has been analyzed under alternating thermal load. Taking into account the fatigue damage due to both average temperature and temperature difference in cross section, an analytical method is proposed by using the models of residual strength and fatigue cumulative damage. First of all, according to the principle of fatigue cumulative damage equal, the frequency of multi-level disturbance stress load caused by temperature difference in cross section is equivalent to the times of constant amplitude stress load action under average temperature, thus both thermal stress loads will be unified for a constant amplitude load, then fatigue reliability can be analyzed by applying the residual strength model based on the theory of dynamic stress-strength interference, finally, the dynamic reliability of the structure in the comprehensive consideration of both thermal fatigue state is obtained. This method not only avoids the direct use of the critical damage value of the cumulated fatigue damage theory which is difficult to determine the problem, but also reflect the real situation of fatigue damage of metal. In the end, take Hubble Space Telescope as an example ,the dynamic reliability of the main beam with the role of cycle fatigue thermal load is analyzed ,and some meaningful conclusions are drawed.
2013, Vol. 34 
