Hale Patrick, Ng Eu-Gene
Department of Mechanical Engineering, McMaster University, 1280 Main St. W, Hamilton, ON L8S 4L8, Canada.
Materials (Basel). 2021 Mar 2;14(5):1161. doi: 10.3390/ma14051161.
When drilling Carbon Fibre-Reinforced Plastic (CFRP) materials, achieving acceptable hole quality is challenging while balancing productivity and tool wear. Numerical models are important tools for the optimization of drilling CFRP materials in terms of material removal rate and hole quality. In this research, a macro-Finite Element (FE) model was developed to accurately predict the effect of drill tip geometry on hole entry and exit quality. The macro-mechanical material model was developed treating the Fiber-Reinforced Plastic (FRP) as an Equivalent Homogeneous Material (EHM). To reduce computational time, a numerical analysis was performed to investigate the influence of mass scaling, bulk viscosity, friction, strain rate strengthening, and cohesive surface modelling. A consideration must be made to minimize the dynamic effects in the FE prediction. The experimental work was carried out to investigate the effect of drill tip geometry on drilling forces and hole quality and to validate the FE results. The geometry of the drills used were either double-point angle or a "candle-stick" profile. The 3D drilling model accurately predicts the thrust force and hole quality generated by the two different drills. The results highlight the improvement in predicted results with the inclusion of cohesive surface modelling. The force signature profiles between the simulated and experimental results were similar. Furthermore, the difference between the predicted thrust force and those measured were less than 9%. When drilling with a double-angle drill tip, the inter-ply damage was reduced. This trend was observed in FE prediction.
在钻削碳纤维增强塑料（CFRP）材料时，要在平衡生产率和刀具磨损的同时实现可接受的孔质量具有挑战性。数值模型是在材料去除率和孔质量方面优化钻削CFRP材料的重要工具。在本研究中，开发了一个宏观有限元（FE）模型，以准确预测钻头几何形状对孔入口和出口质量的影响。将纤维增强塑料（FRP）视为等效均质材料（EHM），开发了宏观力学材料模型。为了减少计算时间，进行了数值分析，以研究质量缩放、体积粘性、摩擦、应变率强化和粘结表面建模的影响。必须考虑在有限元预测中最小化动态效应。开展了实验工作，以研究钻头几何形状对钻削力和孔质量的影响，并验证有限元结果。所使用钻头的几何形状为双点角或“烛台”轮廓。三维钻削模型准确预测了两种不同钻头产生的推力和孔质量。结果突出了包含粘结表面建模后预测结果的改进。模拟结果与实验结果之间的力特征曲线相似。此外，预测推力与实测推力之间的差异小于9%。使用双角钻头钻削时，层间损伤减少。在有限元预测中观察到了这种趋势。
