高效求解结构体系可靠度的新方法

传统的结构体系可靠度分析方法主要依赖于结构失效路径的分枝和约界技术,难以识别主要失效模式且结构体系失效概率计算工作量巨大。为了提高结构体系可靠度计算效率,以β-约界法和联合失效概率分枝约界法为基础,提出了一种快速求解结构体系可靠度分析方法。首先利用结构分析原理,推导出结构单元的安全余量函数并求出其对应的失效概率,拆除失效概率最大值对应的杆件并施以虚拟力形成新的结构,然后再对新的结构重新分析。循环上述步骤,直至结构形成机构为止,并利用构件的失效概率计算结构体系可靠度。算例对比研究表明,该方法计算过程简单、计算精度较高,可以获得结构的失效路径,适合于大型结构的体系可靠度计算。

A NEW METHOD FOR EFFICIENT SOLUTION OF STRUCTURAL SYSTEM RELIABILITY

The traditional reliability analysis method of structural system mainly depends on the branch and bound technology of the structure failure path,leading to that identifying the main failure mode is very difficult and the calculation work of the system failure probability is huge.In view of this,combined with the beta bound method and the joint failure probability branch bound method,a new method that could fastly and efficiently solve the structural system reliability was put forward.Firstly,the safety margin functions of structural element and the corresponding failure probability were determined by applying the structure analysis principle,and the element with the maximal value of failure probability was then removed and substituted by virtual force to form a new structure,and then the reanalysis for the new structure was carried out.The steps above was recycled until the mechanism was formed,and then the structure system reliability was finally calculated by using the failure probability of the component.The comparative analysis of the cases show that the proposed method is simple,less calculating workload,high efficient calculation accuracy and available failure path available,which is very suitable to calculate the system reliability calculation for large scale structure.