基于随机有限元方法的机械结构可靠性评估

Reliability assessment for mechanical structure based on stochastic finite element method

采用随机有限元方法研究复杂载荷条件下某机械结构组件的可靠性特性.考虑工作状态和运输状态,获取组件的载荷特性及其计算模型;利用Ansys软件建立组件有限元分析模型,分析不同工况下组件的静力学和动力学特性,包括应力应变、固有频率、振型、风载静响应以及随机振动响应分析等.基于拉丁超立方抽样的蒙特卡洛方法,将载荷和材料的屈服强度作为随机输入变量,利用随机有限元模型评估风载和路面载荷交互作用下组件的可靠度.在此基础上,分析影响结构可靠性的灵敏度参数.结果表明,该方法能够有效地评估动态工作环境下结构件的可靠性特性,为此类系统的可靠性设计提供理论依据.

Stochastic finite element method （SFEM） is adopted to evaluate the reliability characteris- tics of a mechanical structural assembly. The load characteristics and its calculating model of the as- sembly are obtained by considering both the working and transportation situation. The corresponding finite element analysis model is established with Ansys software. The static and dynamic perform- ances of the components including stress-strain behavior, inherent frequency mode of vibration, stat- ic response of wind load, and random vibration response analysis, under different situations are ob- tained. Based on the Monte Carlo simulation with the Latin hypercube sampling method, the load and the yield strength of material are selected as stochastic variables, and then SFEM is used to as- sess the reliability of the assembly which is undergoing the interaction of wind load and road load. On this basis, the parametric sensitivity analysis for the assembly＇s structural reliability is carded out. The results show that SFEM can evaluate the structural reliability under dynamic environments effectively, providing a theoretical foundation for the reliability design of such systems.