多种失效模式下的机械零件动态可靠性模型

考虑共因失效和随机载荷作用次数对可靠性的影响,建立了零件在多种失效模式下的动态可靠性模型。指出共因失效同样存在于零部件的失效中,运用应力-强度干涉模型和顺序统计量理论建立了多种失效模式下载荷多次作用时的零件可靠性模型以及零件动态可靠性模型。以齿轮的可靠度计算为例,研究了零件可靠度和失效率随时间的变化规律。研究表明,当零件强度不退化或退化不明显时,零件的可靠度随时间逐渐降低,失效率曲线具有浴盆曲线前两个阶段的特征。

Time-dependent Reliability Model of Component with Multiple Failure Modes

The effect of common cause failure,as a mode of dependent failure and the times of load action on reliability was considered and the time-dependent reliability model of a component with multiple failure modes was developed.It is pointed out that the common cause failure also exists in the mechanical components widely.Then,the reliability model under random repeated load and the time-dependent reliability model of a component with multiple failure modes were derived with the stress-strength interference model and the order statistic theory.Taking the reliability calculation of a gear as an example,the relationship between reliability and time and that between the failure rate and time were studied.The results show that when strength degradation can be neglected,the reliability of a component decreases with time and the failure rate curve has the feature of two former sections of the bathtub curve.