复合材料整体成型过程分层缺陷动态扩展研究

分层是复合材料层合板最主要的缺陷/损伤形式,当前研究多集中于复合材料使用过程中的分层损伤,对制造过程中的分层缺陷研究较少。复合材料层合板的分层缺陷在整体成型过程中因不均匀温度场、非对称结构等原因易发生扩展,采用预埋隔离纸模拟分层缺陷,研究分层缺陷在整体成型过程中的扩展行为,对分层扩展的驱动力进行了计算分析,并通过分析热循环对T300/QY8911复合材料层合板界面性能的影响以及计算裂纹尖端能量释放率,从实验研究和有限元计算两方面证明了分层扩展是一个动态过程。研究结果表明,热残余应力是T300/QY8911复合材料层合板整体成型过程中发生分层缺陷扩展的主要驱动力;增加热循环次数和提高热循环温度会显著降低T300/QY8911复合材料层合板的层间剪切强度,当能量释放率降低到低于层间断裂韧性值时,分层动态扩展过程则停止。

Dynamic Propagation of Delamination Defects in Composite Laminates During Integral Forming Process

Delamination is the most important defect/damage form of composite laminates.At present,most researches focus on the delamination damage in the use of composite materials,but few on the delamination defects in the manufacturing process.The delamination defects of composite laminates are easy to propagate due to the uneven temperature field and asymmetric structures in the integral forming process.Embedded anti-sticking paper is used to simulate the delamination defects,and the delamination propagation behavior in the integral forming process is studied.The driving force of the delamination propagation is calculated and analyzed.By analyzing the effect of thermal cycling on the interfacial properties of T300/QY8911 composite laminates and calculating the energy release rate at the crack tip,it is proved that the delamination propagation is a dynamic process from both experimental study and finite element calculation.The results show that the thermal residual stress is the main driving force of the delamination propagation in the integral forming process of T300/QY8911 composite laminates.Increasing the number of thermal cycles and increasing the thermal cycle temperature can significantly reduce the interlaminar shear strength of T300/QY8911 composite laminates.When the energy release rate is lower than the interlaminar fracture toughness,the delamination dynamic propagation process of T300/QY8911 composite laminates stops.