多失效模式机械零件可靠性灵敏度估计

机械零件的失效往往存在多种失效模式,且这些失效模式对可靠性灵敏度均有影响,因此在进行可靠性灵敏度估计时,要充分考虑零件的各个潜在失效模式。提出一种多失效模式机械零件可靠性灵敏度分析的数值方法。运用随机摄动技术和四阶矩技术,求得各失效模式功能函数的前四阶矩及可靠性指标,解决了随机变量分布类型未知时,各失效模式的可靠度计算问题。根据机械零件失效模式较少的特点,将零件的潜在失效模式视为串联关系,则零件整体的失效即为失效模式的串联失效。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可靠性灵敏度的计算公式。数值算例表明所述方法可快速有效地估计多失效模式机械零件的可靠性灵敏度,且适用于非线性功能函数的情况。

Reliability Sensitivity Estimation of Mechanical Components with Multiple Failure Modes

Several potential failure modes may occur when mechanical components fail.For that all the failure modes have a certain impact on the reliability sensitivity of the components,it is necessary to take each failure mode into account as a reliability sensitivity estimation is performed.A reliability sensitivity analysis method for mechanical components with multiple failure modes is proposed.Concerning the unknown distributions of random variables,the random perturbation technique and the fourth moment method are employed to respectively calculate the first four moments and the reliability index of each performance function of the failure mode.The potential failure modes,only a few existed in the component,are regarded in series,and the failure of the component is thus the failure of a series system.The calculating formulas of reliability sensitivity with respect to the mean and variance of random variables are derived with the gradient method.The numerical example illustrates that the proposed method could quickly and effectively estimate the reliability sensitivity of the mechanical components with multiple failure modes,and is also applicable for nonlinear performance functions.