基于CFRP层合板钻削轴向力时变曲线的钻头几何形状分析

为探索能够实现碳纤维增强复合材料（CFRP）层合板低损制孔的钻头几何形状，采用4种不同几何形状的钻头，对T800级CFRP层合板进行钻孔实验研究，分析了钻头几何形状对钻削轴向力的影响，探讨了钻削轴向力与分层损伤之间的关系。结果表明:轴向力归零速度与出口分层因子有较好的正相关性，可采用钻削轴向力归零速度来表征钻头几何形状对CFRP层合板钻孔的适用性能。同时，实验发现切削区域具有多阶段几何特征的钻头，在钻出工件底部时轴向力是分阶段缓慢归零，出口分层因子较小。 

Analysis of drilling bit geometry based on time varying curve of drilling thrust force for CFRP composite laminates

In order to investigate the drilling bitgeometry of carbon fiber reinforced composite (CFRP) laminates which achieves low defect, T800 CFRP laminates were studied by drilling experiments adopting four kinds of different geometry for drill bits. The effect of drill bit geometry on thrust force of drilling was analyzed. The relationship between thrust force of drilling and delamination damage was discussed. The results show that dropping speed of thrust force and outlet delamination factor have a good positive correlation. Dropping speed of thrust force can characterize the applicability of drill bit geometry to CFRP laminates drilling. In addition, the experiments show that cutting areas of drill bits which have multi-step geometric characters would cause thrust force returning to zero slowly in multi stages during drilling through the exit of the workpiece, and generating lower delamination factor at exit.