压缩预应力对复合材料层板抗冲击损伤性能的影响

为确定压缩预应力对复合材料层板抗冲击损伤性能的影响，首先对不同压缩预应力下的碳纤维/双马树脂CCF300/5428层板进行了低速冲击和准静态压痕试验，然后通过热揭层和冲击后压缩试验分别得到了层板分层面积和剩余强度。结果表明:压缩预应力会大幅降低层板的接触刚度和弯曲刚度，从而导致相同冲击能量下层板凹坑深度和背部基体开裂长度增大；对于准静态压痕过程和相同冲击能量下的冲击过程，分层起始载荷和峰值载荷均随压缩预应力的增大而减小；在相同冲击能量下，随着压缩预应力的增大，层板内部分层总面积及冲击能量吸收比不断增大，剩余压缩强度不断降低。因此，压缩预应力会降低复合材料层板的冲击损伤阻抗，对损伤容限性能不利，在对承受压缩载荷结构的试验验证过程中应考虑压缩预应力对抗冲击损伤性能的影响。 

Effects of compressive preload on impact damage performance of composite laminates

In order to determine the effects of compressive preload on impact damage performance of composite laminates,low-velocity impact and quasi-static indentation tests were carried out on carbon fiber/bismaleimide resin CCF300/5428 laminates under different compressive preloads firstly.Then,delamination area and residual strength of the laminates were obtained by thermally deplying and compression after impact tests respectively.The results show that compressive preload will reduce the contact stiffness and bending stiffness of the laminates significantly, which causes the increases in dent depth and crack length of back matrix for the laminates under the same impact en-ergy.For the quasi-static indentation process and impact processes under the same impact energy,both of delamina-tion initiation load and peak load decrease with the increase of the compressive preload.Under the same impact ener-gy,total delamination area in the laminates and absorbed impact energy ratio increase continually with the increase of compressive preload,leads to the continuous reduction in residual compressive strength.In conclusion,compressive preload will reduce the impact damage resistance of composite laminates and is unfavorable to the damage tolerance performance,which means that it is necessary to take the effects of compressive preload on impact damage perform-ance into consideration during the test verification process of the structures under compressive load.