论文部分内容阅读
针对桁架结构系统 ,采用随机有限元法 (SFEM)计算结构系统的响应量 ;考虑内力重新分配 ,建立失效模式的安全余量方程 ,用验算点法计算失效模式安全余量的可靠性指标 ;用改进的分枝限界法 ,寻找主要失效模式 ,通过对主要失效模式方程线性化研究 ,计算失效模式安全余量之间的相关系数 ;最后用PNET法计算出结构系统的失效概率。同时给出多随机变量的结构系统可靠度的敏度表达式 ,采用最佳矢量法 ,求解了大型桁架结构系统基于可靠性指标约束下的最小重量的优化设计问题。最后 ,给出了实际算例 ,计算结果表明 :采用随机有限元法能更好地考虑结构系统的多个随机变量对系统可靠性产生的影响 ;所采用的可靠性分析方法和优化方法是有效的
For truss structure system, SFEM is used to calculate the response of structural system. Considering internal force redistribution, the safety margin equation of failure mode is established, and the reliability index of failure mode safety margin is calculated by check point method. The improved branch-and-bound method is used to find the main failure modes. The linear correlation of the main failure mode equations is used to calculate the correlation coefficient between the safety margins of the failure modes. Finally, the failure probability of the structural system is calculated by PNET method. At the same time, the sensitivity expression of the structural system with multiple random variables is given. The optimal vector method is used to solve the optimal design problem of the minimum weight under the restraint of the reliability index of the large truss structure system. Finally, an actual example is given. The calculation results show that the use of stochastic finite element method can better consider the effect of multiple random variables of the structural system on system reliability. The reliability analysis method and optimization method adopted are effective of