纤维桥连对复合材料Ⅰ型层间断裂韧性的影响

 采用ASTM D 5528标准对T700/9916复合材料单向板进行了试验,研究了双悬臂梁(DCB)试验中桥连纤维对Ⅰ型层间断裂韧性的影响。根据试验观察,提出桥连区存在单(s区域)、双纤维桥连区域(d区域)的分析模型,其中d区域内一点上桥连纤维的数量是s区域的两倍;通过对桥连纤维和悬臂梁相互作用的分析,推导出呈指数形式递减的单根纤维桥连力-转角函数。由此得到整个悬臂梁的桥连力函数,并对DCB试验进行了分析,得到的模拟曲线与试验曲线吻合较好。研究结果表明本文提出的纤维桥连模型能够真实地反映桥连纤维在裂纹扩展过程中的作用方式。

Influence of Fiber Bridging on Mode Ⅰ Interlaminar Fracture Toughness of Composites

T700/9916 composite laminate specimens are tested according to ASTM D 5528 standards, and the fiber bridging effect on Model I interlaminar fracture toughness is investigated in double cantilever beam (DCB) tests. From experimental observation, a model with single (s zone) and double fiber bridging zone (d zone) is proposed. The number of bridging fibers on a point of the d zone is twice as large as that on a point of the s zone. From an interaction analysis between the bridging fibers and the beam, an exponentially decreasing function of single fiber bridging force versus angle is built. Based on the analysis above, a DCB model involving the bridging force function of the whole beam is established. The simulation results show a satisfactory agreement with test results. The present fiber bridging model reflects how bridging fibers act in the process of crack propagation.