考虑载荷作用次数的多失效模式扭力轴灵敏度分析

机械构件的不同的失效模式之间具有一定的相关性,而且随机载荷作用次数对机械构件的可靠性有一定程度的影响。因此对机械构件进行可靠性灵敏度分析时,需要充分考虑其不同失效模式和载荷作用次数的影响。通过运用顺序统计量理论考虑载荷多次作用以及多种失效模式条件下机械构件可靠性及可靠性灵敏度的变化规律,运用随机摄动理论和四阶矩技术,建立一种考虑载荷作用次数的多失效模式机械构件可靠性灵敏度分析数值方法的应力强度干涉模型。在随机变量前四阶矩已知的情况下,结合灵敏度分析的梯度算法,推导出关于随机变量均值和方差的灵敏度计算公式。以某履带车辆底盘扭力轴为例进行计算,得到其可靠度随载荷作用次数、随机变量均值和方差而改变的可靠性灵敏度变化曲线,为扭力轴的可靠性优化提供一定的理论依据。研究成果可以推广到相关机械可靠性灵敏度设计和结构优化领域,具有非常重要的实用意义。

Sensitivity analysis of the torque axis considering the times of load action with Multiple Failure Modes

Several potential failure modes may occur when mechanical components fail, and they have several correlation in some way, for that the condition of load action many times have an impact on the reliability of mechanical components, thus it was necessary to take all the failure modes and load action many times into account when study the mechanical reliability sensitivity analysis. Combined the order statistic theory to study the influence of load action time on the reliability and sensitivity calculation, applying the probabilistic perturbation method and the Edgeworth series technique, a reliability calculation model of mechanical components with multiple failure modes and load action many times modes had developed using the stress-strength interference mode. The calculating formulas of reliability sensitivity with respect to the mean and variance of random variables were derived with the gradient method, according to the result of the torque axis reliability sensitivity analysis, the curves of reliabilities and sensitivities were obtained, and the production can be very useful if it extended to correlated area of machine sensitivity design.