载荷共享并联系统疲劳累积损伤可靠性模型

Reliability Model of Cumulative Fatigue Damage of Load-Sharing Parallel System

针对存在载荷传递、分担的并联系统,传统的并联系统可靠性模型已不适用.为了有效处理载荷共享并联系统的可靠性问题,首先分析了并联系统的相关失效,并分步计算并联系统可靠度,应用全概率公式和Miner理论对并联系统进行了疲劳累积损伤可靠性建模.其次,运用Monte Carlo方法对零件寿命服从Weibull分布的并联系统可靠度进行了模拟计算,同时对零件寿命服从对数正态分布的并联系统可靠度显式计算公式进行了推导.建立了变应力作用下并联系统疲劳累积损伤可靠性模型.

The conventional reliability model of parallel system is inadaptable to the parallel system where the load is transferred and shared. Analyzing the dependent failure and stepwise computing the reliability of a parallel system, the reliability model of cumulative fatigue damage of a load sharing parallel system is developed according to the total probability formula and Miner theory. Then, a simulative computation is done by the Monte Carlo method for the reliability of parallel system in which the service life of a component follows the Weibull distribution, with the explicit formula of system reliability deduced for the service life of a component that follows the logarithm normal distribution. As a result, a reliability model of cumulative fatigue damage for the parallel system under the action of varying stress is developed.