对称角铺设矩形复合材料叠层板受低速冲击时的应力波传及解层破坏分析

采用碰撞力分段模型和一阶剪切理论分析了给定初始速度的铁球与四边简支的复合材料叠层板中心发生碰撞的动力学行为，包括碰撞力及接触时间的变化规律、叠层板的振动响应、应力波传、表面沉陷等。并根据忽略厚度的界面模型假设及简化的Tsai Wu张量理论对复合材料叠层板的解层破坏进行了计算和分析，并给出了破坏区大小与铁球初始速度的关系。研究表明:碰撞力与铁球的初始速度成正比；复合材料叠层板中应力波传沿固定方向的相速度在各层内相同，拉伸应力波传速度沿纤维总体占优的方向大于其垂直的方向，而剪切应力波传速度则相反。即使在较低的初始碰撞速度下， 复合材料叠层板的解层破坏也很明显，并且破坏区域随初始碰撞速度的增大而不断扩展，其形状也会发生改变。 

Analysis to propagation of stress-wave and delaminating damages of layer-symmetrical composite laminates subjected to low velocity impact

By adopting a piecewise impact force model and the First Shearing Deformation Theory (FSDT), the dynamic behavior of composite laminates with simply supported boundary was analyzed under low velocity impact in the geometric center by a steel ball，including the evolution rules of the impact force and contact time with relations to impact velocity，and vibration response of laminates，stress-wave propagation，as well as surface dent. The delamination area of the laminates was calculated and analyzed by adopting hypothesis of no thickness interface with a simplified version of Tsai-Wu‘s Damage Criteria, and the relation between size of delamination area and initial velocity of steel ball is also presented. The study shows that the impact force is in proportion to the initial velocity of the steel ball. And the phase velocity of stress-wave propagation is the same in each layer of composite laminates for a given direction. The velocity of tensional stress-wave propagation in the direction of fiber concentration is faster than that in the other directions，while it is on the contrary for shearing stress-wave propagation. The delamination of composite laminates occurs even under low velocity impact. The damage area expands and its shape changes with increasing the impact velocity.