レーザ誘起衝撃波を用いた航空宇宙材料の衝撃破壊に関する研究

我们使用激光加速铝飞片测试了碳纤维增强塑料(CFRP)层压板的超高速冲击试验。用短脉冲强激光辐照铝飞片，加速到6~9公里/S。我们用高速分幅相机成功地观测了CFRP靶材的变形和断裂过程。结果表明，碳纤维复合材料是从靶板碰撞表面飞溅出来的。靶材背面的变形速度约为100~700m/次。冲击试验结束后，利用光学显微镜、扫描电子显微镜和激光显微镜研究了碳纤维复合材料靶材的损伤情况。我们在传单撞击的背面发现了I型的断裂面。在背部略偏离撞击点的位置观察到II型损伤。通过对靶材断面的观察，发现了层间多层脱层现象。据此，提出了CFRP层合板在超高速冲击载荷下的断裂模型。裂纹由层裂(I型)2引发，然后在剪切力(II型)3作用下沿碳纤维扩展。最后，纤维在背面被拉伸断裂。介绍了从实验取景图像和CFRP靶材的损伤观察推测的断裂机理。具有层裂的冲击变形与实验结果定性一致。

We examined hyper-velocity impact tests of CFRP (carbon fiber reinforced plastics) laminates using laser-accelerated Al flyers. Al flyers were accelerated to 6〜9km/s by irradiation of a short-pulsed intense laser beam. We succeeded in observing the deformation and fracture processes of the CFRP targets with a high-speed framing camera. It was found that the CFRP was splashed out from the collision surface of the targets. The deformation velocity of the back surface of the targets was about 100〜700m/s.After the impact experiments, we investigated damages of the CFRP target with a optical microscope, a scanning electron microscope (SEM) and a laser microscope. We found fracture surfaces of mode I type exactly on the back of the flyer impact. Damages of mode II type were observed in the back where it came off the impact point a little. Multi-interlaminar delaminations were discovered by observation of the section of the targets.The following fracture model of CFRP laminates under hyper-velocity impact loading is proposed as these results.1. A crack is initiated by spallation (Mode I)2. Then, the crack is propagated along carbon fibers by shear force (Mode II)3. Finally, fibers at the back surface were broken by tensionThree-dimensional simulations of the hyper-velocity impact were performed using the Dyna3D. We introduced the fracture mechanisms presumed from the framing images at the experiments and the damage observation of the CFRP targets. Impact deformations with spallation agreed with the experiment results qualitatively.