基于四要素的机械零部件失效率计算模型

摘要

The factors affecting the typical failure rate curve were analyzed, and four elements including load, strength, strength degradation and life index(namely, the number of load application and time) were proposed for calculating the failure rate of components. Taking the number of load application and time as the life index, respectively, the failure rate models of components consisting of four elements were developed, which can embody the parameters of load, strength, strength degradation and life. Then, the behaviors of the reliability and failure rate of components changing as the life index were studied. The results show that the failure rate curves of components have the partial or whole characteristics of bathtub curve. For different parameters of load, strength and the rule of strength degradation, the failure rate curves of components have different shapes. The models derived herein can calculate the failure rate of components as long as the known parameters of load, strength and its degradation and life index, and can direct the reliability-based design of components more scientifically.%分析了影响典型失效率曲线变化的因素，提出了零部件失效率计算的四要素，即载荷、强度、强度退化规律以及寿命指标(载荷作用次数或时间)。分别在以载荷作用次数和时间为寿命度量指标框架下，建立了能够全面地体现载荷、强度、强度退化规律以及寿命指标等参数影响的零部件失效率计算四要素模型，并研究了零部件可靠度与失效率随寿命指标的变化规律。研究表明，零部件的可靠度随寿命指标的增大而逐渐减小，零部件的失效率随寿命指标变化具有浴盆曲线全部(或部分)特征。对于不同的强度分布、载荷分布和强度退化规律组合，零部件具有不同的可靠度，失效率曲线具有不同的形状。所建立的失效率模型无需依赖产品的失效数据信息，而只要在载荷、强度、强度退化规律以及寿命指标等参数已知的情况下便可以准确地计算零部件的失效率，可更好地在设计阶段指导零部件的可靠性设计。