考虑失效模式相关性和载荷作用次数的零件可靠性分析

Reliability Analysis of Parts with the Relevance of Failure Modes and the Frequency of Loading Actions

机械零部件在实际工作过程中一般存在多种失效模式,且这些失效模式之间具有一定相关性。另外,机械零部件所承受的载荷也不是固定不变的,常常具有随机性和多次重复性特点。根据随机载荷作用统计学意义,在对零件各失效模式未作相互独立假设情况下,引入条件可靠度,运用"应力—强度"干涉理论建立了多种失效模式相关下的零件可靠性模型;然后在此基础上,考虑载荷作用次数对零件可靠性的影响,并运用顺序统计理论,建立载荷多次作用下的零件可靠性模型;最后,运用Monte Carlo模拟方法对载荷多次作用下的零件可靠性模型进行仿真实验,总结了载荷作用次数对零件可靠度的影响规律。结果表明,零件可靠度随载荷作用次数增加会呈现逐渐下降趋势;载荷作用次数不变时,零件失效模式数越多,零件可靠度越低。

Mechanical parts generally have multiple failure modes in the actual working process, and there is a certain correlation between these failure modes. In addition, the load on mechanical components is not fixed, and often has randomness and multiple repeatability. According to the statistical significance of the random load action, under the assumption that the failure modes of the parts are not independent of each other, the condition reliability is introduced, and the "stress-strength" interference theory is used to establish the part reliability model under various failure modes. Then, based on this, consider the influence of the number of load times on the reliability of the parts, and use the sequential statistical theory to establish the part reliability model under the load multiple times. Finally, the Monte Carlo simulation method is used to load the parts under multiple loads. The reliability model is simulated and the influence law of the number of loads on the reliability of the parts is summarized. The results show that the reliability of parts will gradually decrease with the increase of the number of times of load. When the number of times of load is constant, the more the number of parts failure modes, the lower the reliability of parts.