结构非概率可靠性模型在断裂力学分析中的应用研究

Application of Structural Non-probabilistic Reliability Model in Fracture Mechanics Analysis

工程实际中的构件或材料由于不可避免地存在缺陷或裂纹,其强度大大低于理想模型的强度.考虑含裂纹结构的性能参数、几何参数及作用载荷、缺陷特征等的不确定性的可靠性分析具有重要的工程实际意义.针对大型、贵重构件或材料样本数据少、统计信息缺乏的情况,提出了含缺陷结构断裂失效的非概率可靠性分析方法.对非概率可靠性度量方法进行了分析、比较,由于以断裂判据建立的功能函数往往为多维非线性方程,针对非概率集合可靠性模型的计算困难,提出用Monte-Carlo模拟方法计算非概率可靠度具有易实现、精度高的特点.本文方法克服了概率断裂力学(PFM)方法需要大量统计数据的局限性,具有重要的工程应用价值.实例分析对本文方法的可行性和有效性进行了验证.

The strength of many structures is greatly reduced since that defect inevitably exists.It is important to evaluate the reliability of defect structure with much uncertain information.Due to the scarcity of statistical data for large and valuable structure,a non-probabilistic reliability analysis model of defect structure based on fracture failure mode was proposed.Three non-probabilistic reliability indices were compared and researched.In view of the difficulties for non-probabilistic set-based model for structural reliability with multidimensional nonlinear equation,Monte-Carlo method was designed.Combined with fracture criteria,the non-probabilistic reliability model of defect structure was set up.The limitation of PFM for mass data could be overcome.A given example showed that the proposed methodology was slightly conservative in application and had feasibility and reasonableness.