关于受冲击编织复合板的一个例子(实验特征及模型)

本文对厚编织复合材料板由硬的钢圆柱弹丸穿孔问题进行了研究．实验研究表明连续穿孔时在侵彻弹丸附近发生材料的横向剪切以及面内中间层分层的传播，而面内中间层分层的传播将导致纤维的拉伸断裂?由于冲击加载并不是瞬时的，这导致了横向剪切．在接近穿孔极限速度的入射速度(V50)范围内，这一机制依赖于复合材料板的厚度和中间层剪切强度．中间层分层的传播则由弹丸与靶接触时引起的弯曲波所致．由弯曲波所致的面内分层传播这一现象分别引起了面内圆形损伤和沿厚度内的锥形损伤．同时分层传播由弯曲波速所控制，其依赖于纤维的弹性特征、编织层的失效时间(其直接由编织层的弯曲刚度决定)及材料一些特定的失效参数．另外由于增加了拉伸破坏吸收的能量，分层传播还改进了材料的冲击强度．本文提出了一个分析模型来确定分层区域和靶的穿孔极限速度．采用这一模型对穿孔极限速度的计算结果表明其与实验值符合良好．

Dynamic Fracture of Composites An example about impacted woven composite plates (Experimental Characterization and Modelling)

The study is concerned with perforation of thick woven composite plates by hard steel cylinder. Experimental investigations show that perforation successively involves transverse shear of material around penetrator and propagation of interlaminar in-plane delamination which induces tension breaking of fibers. Transverse shear is due it that impact loading is not instantaneous. In the range of incident velocities near to the perforation limit ve-locity(V50) , this mechanism depends on thickness and interlaminar shear strength of composite plate. Propagation of interlaminar delaminations is caused by flexion waves created at the contact between the projectile and the target. Delamination propagate in-plate with flexion waves. This phenomenon causes circular and conical damages respectively in-plane and through-thickness of the target. Propagation of delaminadons is simultaneous controlled by flexion waves velocity, which depends on elastic characteristics of fibers, and failure time of layers which is governed at once by flexural stiffness of the last ones and specific failure parameters of material. Furthermore, propagation of delaminadons improves the impact strength of material by increasing tension breaking energy absorption. An analytical energetic model is developed to determine delaminated areas and perforation limit velocities of the target. Results of this model show a good agreement between experimental and calculated values of perforation limit velocities.