Two different experimental techniques are employed to visualize the impact damage generated by a low-velocity impact on a carbon-fibre reinforced-polymer (CFRP) composite laminate. At the relatively low impact-velocity of 1.69 m.s⁻¹, and a corresponding impact energy of 7.5 J, used in the present work the damage induced in the CFRP panel is barely visible to the naked eye but the techniques of ultrasonic C-scan and X-ray computed tomography (CT) can detect the damage that has occurred. This damage is mostly interlaminar damage, i.e. delaminations, between the plies due to a change in modulus from one ply to the next in the laminate. This interlaminar damage is usually accompanied by intralaminar damage, e.g. matrix cracking, in the ply itself. The type and extent of damage detected from using these two techniques is discussed and the relative merits of these techniques are compared. In general, the CT gave the better resolved picture of damage but the lateral extent of the damage was underestimated relative to C-scan which was more sensitive to very fine delamination cracks. In addition, a numerical approach, based on a finite-element analysis model, is employed to predict the type, location and extent of damage generated by the impact event and the modelling predictions are compared to the experimental results.

采用两种不同的实验技术来可视化碳纤维增强聚合物 (CFRP) 复合材料层压板低速冲击所产生的冲击损伤。在当前工作中使用的相对较低的冲击速度 1.69 ms ^-1和相应的冲击能量 7.5 J 下，CFRP 面板中引起的损坏肉眼几乎看不见，但超声波 C 扫描技术和X 射线计算机断层扫描 (CT) 可以检测已发生的损坏。这种损坏主要是层间损坏，即由于层压材料中从一层到下一层的模量变化而导致层之间的分层。这种层间损坏通常伴随着层本身的层内损坏，例如基体开裂。讨论了使用这两种技术检测到的损坏的类型和程度，并比较了这些技术的相对优点。一般来说，CT 给出了更清晰的损伤图像，但相对于 C 扫描，损伤的横向范围被低估了，C 扫描对非常细的分层裂纹更敏感。此外，采用基于有限元分析模型的数值方法来预测撞击事件产生的损坏的类型、位置和程度，并将模型预测与实验结果进行比较。