正常使用极限状态下隐式功能函数结构可靠度计算  

Reliability Calculation of Implicit Function Structure in Service Ability Limit State

作　　者：金波[1] 周旺[1] 唐丽莹 李梓溢 姜早龙[1] JIN Bo;ZHOU Wang;TANG Liying;LI Ziyi;JIANG Zaolong(College of Civil Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]湖南大学土木工程学院

出　　处：《湖南大学学报（自然科学版）》2020年第1期116-122,共7页Journal of Hunan University:Natural Sciences

基　　金：湖南省交通厅科技项目(201525)~~

摘　　要：提出了一种适用于具有复杂隐式功能函数的钢桁架结构可靠度计算方法.采用神经网络逼近正常使用极限状态下隐式功能函数,基于可靠度指标的几何意义,运用新改进的遗传算法搜索钢桁架可靠度指标最优解及验算点.通过两个算例,分别使用JC法和蒙特卡洛重要抽样法验证了新改进的遗传算法的准确性和有效性.结果表明,新改进的遗传算法与蒙特卡洛法计算的钢桁架可靠度指标相对误差仅为0.23%;且对于小概率失效结构,引入的自适应随机变量能有效改善传统方法中初始种群基因不良的问题.该方法在计算复杂隐式功能函数结构可靠度指标时,具有计算速度快、计算简单、精度高等优点.A reliability calculation method is proposed to calculate the reliability of structure with complex implicit function like steel truss structures.It firstly adopts the neural network to approach the implicit function in service ability limit state and NGA(New Genetic Algorithm)is employed to obtain the optimal solution of reliability index of steel truss structures and its design point on the basis of the geometric implication of reliability index.Finally,JC method and Monte Carlo Critical Sampling Method are introduced,respectively,in two examples to verify the accuracy and validity of NGA.The results manifest that the relative error is only 0.23 percent when NGA and Monte Carlo Method are used,respectively,to calculate the reliability index of steel truss.In addition,the introduction of adaptive random variable can greatly improve the gene of initial population for small probability failure structures.All above prove that NGA is of significance in practical projects for calculating the reliability index of structure with complex implicit function due to its advantages of fast computation speed and high precision.

关 键 词：可靠度指标 隐式功能函数 神经网络 遗传算法 

分 类 号：U442.5[建筑科学—桥梁与隧道工程]