复合材料层合板的可靠性分析方法

基于复合材料层合板的一阶横向剪切变形理论,提出了同时考虑层合板面内和分层破坏的可靠性分析方法。该方法考虑了层间应力对层合板分层的影响,结合Tsai-Hill理论和层合板分层判据,给出了安全余量的表达形式,并考虑了各失效模式之间的相关性。在失效分析过程中,采用蔡氏所提出的刚度退化规律进行刚阵的减缩;利用随机有限元方法对安全余量进行敏度分析,结合改进的一次二阶矩法求解可靠性指标;用改进的分枝限界法寻找主要失效路径;用PNET法计算系统失效概率。计算表明,当考虑分层失效时结构系统失效概率有所增加,这是符合工程实际情况的。因此,设计过程中考虑分层失效是必要的。

A Method of Reliability Analysis For Composite Laminate

Based on the first order transverse shear theory of compose laminate, a method of reliability analysis for composite laminate considering face and delamination failure is proposed. The method considers interlaminar stress influencing on delamination and relativity of failure modes, and gives safe margin expression in the form of Tsai-|Hill theory and the failure criterion of delamination. In the process of failure analysis, reduced member stiffness matrix is calculated by Tsai's stiffness deterioration law. Sensitivity of the safety margin is analyzed by stochastic finite element method. The significant failure modes are identified by the advanced branch-|and-|bound method. Their reliability indexes are calculated by advanced first-|order second-|moment method. The reliability of structural system is evaluated by PNET method. The result indicates that failure probability of structural system increased when considering delamination failure; it is suitable for engineering case. Thus, it is necessary to consider delamination failure in the process of design.