基于渐进损伤分析的复合材料螺栓连接强度包线法研究

针对中国民机采用T800级复合材料这一新材料体系而基础数据匮乏的现状,采用渐进损伤分析(PDA)替代试验以显著降低研究周期和成本。综合渐进损伤方法和工程算法各自的优点,提出以渐进损伤分析替代应力集中减缓因子(SCRFs)测定试验,进而建立强度包线,并进行多钉连接强度预测的数值策略。为验证该数值策略的可行性,针对典型铺层应力集中减缓因子,测定试样,并开展渐进损伤分析,获得了试验件强度预测值来计算应力集中减缓因子,采用旁路载荷修正的强度包线法,绘制了典型铺层复合材料多钉连接旁路载荷修正强度包线,预测多钉连接的失效载荷,并与试验结果进行对比。结果表明:采用该数值策略预测的强度包线、多钉连接的失效载荷和失效模式均与试验结果吻合良好,证明了该数值策略的可行性。

Progressive damage analysis based strength envelope method research for composite bolted joints

Considering the present situation that the foundation data for a new T800 composite system adopted in civil aircraft industries are extremely scarce, a progressive damage method (PDA) substituting the tests can reduce the research period and cost significantly. In conjunction with the progressive damage method and the engineering algorithm, a numerical strategy for the strength prediction of multi-bolt joints is presented. In this strategy, the progressive damage analyses of the samples for determine stress concentration relief factors (SCRFs) were carried out to substitute the physical tests. And the strength envelope was constructed. In order to verify the feasibility of the proposed numerical strategy, a bypass-load modified strength envelope method was adopted. The progressive damage analyses of typical ply for stress concentration relief factors were performed and the predictive value of strength was obtained to calculate the stress concentration relief factors. Modified strength envelope of bolted joints bypass-load for typical ply composite was plotted. The failure load of bolted joints was predicted and compared with test results. It can be found that the strength envelope and the ultimate failure loads as well as failure modes of multi-bolt joints based on the numerical strategy agree well with the test results, which provide evidence for the feasibility of the proposed numerical strategy.