随机载荷作用下轴对称结构模糊可靠度计算方法

Fuzzy reliability analysis of axial symmetrical structure under stochastic load

利用摄动随机有限元法,推导在载荷随机情况下轴对称结构的位移的均值和方差的计算公式,进而计算出单元应力的均值和方差。在强度为随机变量的情况下,把结构从安全状态到失效状态的过渡性考虑成一模糊事件,采用线性隶属函数,计算了轴对称结构的模糊可靠度。计算结果表明,把载荷处理为随机载荷,把失效事件处理为模糊事件,更符合实际情况,为结构可靠性优化设计提供更可靠的信息。

The perturbation stochastic finite element method is adopted to deduce the formulas for the calculation of mean value and deviation of the element displacement in stochastic load situation using perturbation stochastic finite element,and calculating the statistical characteristics of stress for axial symmetry structure,taking the material strength as a stochastic variable and considering the transition from safety state to failure state a fuzzy matter and membership function a liner-function,calculating reliability of axial symmetry structure,the result indicated that load processing is the stochastic load,invalidating matter processing is the fuzzy matter,conforms to the actual situation,provides more reliable information for the built-in reliability optimization design.