基于随机有限元的空间梁板结构系统可靠性分析

Reliability analysis for beam and shell structure based on stochastic finite element method

影响船舶结构系统可靠性的因素有很多,所以有必要对其结构进行可靠性分析.为此采用空间梁元与板元来模拟空间梁板结构,运用将随机有限元法与确定性有限元法相结合的随机有限元理论,采用分枝限界法找出主要失效模式,利用改进的一次二阶矩法计算各失效模式的安全余量,最终利用各失效模式相关性和概率网络估算技术法计算结构系统的失效概率.编制了考虑材料的强度、梁板元的尺寸和外载荷等均为随机变量的三维梁板空间结构问题的随机有限元程序,最后通过实例进行结构系统可靠性分析计算.

The reliability of ship structural system is affected by many factors,so the structural reliability analysis is very necessary.The space beam element and shell element mesh were used to simulate the spatial beam-slab structure.Combined the stochastic finite element method with the certainty of the stochastic finite element theory,major failure modes were identify by branch and bound method,the various failure modes of the safety margins were calculated by first-order second-moment method.Finally,the failure probability of structural system was calculated using the failure mode correlation and PNET method.Considering the material strength,the size of beam and shell element,external load that were random variables in structural problems of three-dimensional beam-slab space,the stochastic finite element program was written.At last,some analysis and calculation were given under simple cases of structural system reliability.