This study presents experimental results of compression after impact (CAI) testing of aluminum honeycomb core sandwich structure with face sheets made of quasi-isotropic carbon/epoxy with two orthogonal directions of testing. In a previous study examining the CAI strength of honeycomb sandwich structure,¹ it was found that that specimens had different CAI strengths depending on whether the core was oriented in the “L” or “W” direction. Since the face sheets were quasi-isotropic and the core should not (theoretically) affect the CAI strength for a given amount of damage (if the specimens fail by face sheet failure), this result was puzzling. In the study presented in this paper, further CAI tests, along with open hole compression testing were used in an attempt to ferret out the cause of the differing CAI strengths in the aforementioned study. The results showed that the lower CAI strength values were not due to the core orientation, but to the change in the quasi-isotropic face sheet ply sequence due to the 90° rotation.

本研究展示了具有两个正交测试方向的准各向同性碳/环氧树脂制成的面板的铝蜂窝芯夹层结构的冲击后压缩 (CAI) 测试的实验结果。在之前的一项研究中，研究了蜂窝夹层结构的 CAI 强度，¹研究发现，根据核心是朝向“L”还是“W”方向，试样具有不同的 CAI 强度。由于面板是准各向同性的，并且芯不应该（理论上）影响给定量损伤的 CAI 强度（如果试样因面板失效而失效），这个结果令人费解。在本文介绍的研究中，进一步的 CAI 测试以及裸眼压缩测试被用来试图找出上述研究中不同 CAI 强度的原因。结果表明，较低的 CAI 强度值不是由于核心方向，而是由于 90° 旋转导致准各向同性面板层顺序的变化。