Abstract This study conducts experimental and numerical studies on the progressive damage occurring during the drilling of composite laminates. In particular, this work focuses on push-out delamination, which occurs at the interface around the drill-exit and is the most critical damage suffered during the drilling process. To investigate the damage progression mechanisms, penetration and interruption drilling tests are performed on composite laminate consisting of quasi-isotropic CFRP plies and fabric GFRP ply (bottom side). After drilling tests, the damage evolution is evaluated using X-ray computed tomography and optical microscopy. Based on the experimental results, a simplified simulation model is established, and damage progression simulation is performed using an explicit dynamic finite element method. The results show that the bending deformation in the bottom two plies triggers the propagation of push-out delamination. Therefore, the extent of delamination is significantly affected by the thickness and the material properties of the bottom plies.

中文翻译：

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复合层压板钻孔中推出分层的实验和数值研究

摘要 本研究对复合材料层压板钻孔过程中发生的渐进损伤进行了实验和数值研究。特别是，这项工作的重点是推出分层，这种分层发生在钻孔出口周围的界面处，是钻孔过程中遭受的最严重的损坏。为了研究损伤进展机制，对由准各向同性 CFRP 层和织物 GFRP 层（底部）组成的复合层压板进行了穿透和中断钻孔测试。钻孔测试后，使用 X 射线计算机断层扫描和光学显微镜评估损伤演变。根据实验结果，建立了简化的仿真模型，并采用显式动力学有限元方法进行损伤进展仿真。结果表明，底部两层的弯曲变形触发了推出分层的传播。因此，分层的程度受底层的厚度和材料特性的显着影响。