Abstract: Carbon fiber reinforced plastics (CFRP) is widely used in the aerospace industry. However, due to the characteristics of anisotropy and poor interlayer connection, the delamination is very easy to occur in the drilling process, which seriously affects the performance of the components. In order to analyze the influence mechanism of drilling temperature on the hole-making delamination of plain-woven CFRP, a thermo-mechanical theoretical model of the delamination formation for the drilling of plain-woven CFRP by using the novel drill is established, based on the elastic foundation beam theory, cohesion mechanics model and thermo-mechanical theory. The results show that when the novel drill candle stick edges (Ⅲ) drill the exit top layer materials, the drilling temperature reaches the maximum value, and this period is the most critical for the formation of the final delamination. The drilling temperature and the delamination gradually decrease with the increase of the spindle speed, and gradually increase with the increase of the feed speed. When the fiber angle (θ) is near 0°/90°/180°/270°, the critical axial force of the interlayer delamination reaches its maximum value, and the delamination is relatively large. When the fiber angle (θ) is around 45°/135°/225°/315°, the critical axial force is the smallest and the delamination is not extremely large. Therefore, the critical force can only reflect the difficulty of generating delamination, but can't determine the final shape and size of the delamination. The prediction of delamination morphology obtained by the thermo-mechanical theoretical model is consistent with the experimental observations. However, the predicted value obtained without considering the temperature is generally small. In addition, the delamination shape of plain-woven CFRP is almost circular.

Key words: carbon fiber-reinforced plastic (CFRP), drilling, critical drilling force, temperature, delamination