Simulation And Experimental Study On Drilling Process Of Carbon Fiber Composites

In recent years,with the strong support of national policies and the promotion of large-scale development of domestic carbon fiber composites,carbon fiber composite drilling technology has developed rapidly in China,followed by the market for the quality of carbon fiber composite materials also put forward higher requirements.However,now the domestic carbon fiber composite drilling technology is not particularly mature,so it may cause a great waste of resources and economic losses.Therefore,it is imperative to combine the computer to simulate the drilling process of carbon fiber composite materials and optimize the traditional drilling process.In this paper,the machining process of 3D biaxial warp knitted carbon fiber composites is studied,the mesoscopic drilling model is established,and through the finite element analysis software Abaqus,the relationship among the spindle speed,feed rate and axial force is analyzed.Finite element simulation of 3D biaxial warp knitted carbon fiber composites has preliminarily been come true.In addition,two different kinds of bit drills with diamond coated carbide bits and PCD bits are used in the experiment,and the drilling force and the hole quality in the drilling process are compared and analyzed.The main research contents of this paper are as follows:(1)The failure model of the unidirectional carbon fiber composites is studied in detail.The cutting deformation and chip formation during the cutting process are analyzed,and the relationship between the formation of chips and the angle of fiber orientation is studied.And then deduces the theoretical formula of cutting force.Based on the standard twist drill,it is concluded that the main damage to the carbon fiber composite material in the drilling process is the Z-direction drilling force which perpendiculars to the surface of the carbon fiber composite.(2)The 3D biaxial warp knitted carbon fiber composites are modeled simply,on this basis,a mesoscopic model of drilling is established.And then the Abaqus finite element analysis software is used to simulate the spindle speed 500 rpm and feed rate 110 mm / min process parameters of the PCD bit under the drilling process,and the change rule of Z-direction drilling force in drilling process is obtained.(3)A low-speed or medium-speed drilling experiment of 3D biaxial warp knitted carbon fiber composites was carried out.And then the drilling force regression model of diamond coated carbide bit and PCD bit under different process parameters was established and verified.As a result,the average error of the two types of drill bits is relatively small,which proves the reliability of the model.And the experimental results are compared with the simulation results under the same process parameters.(4)The main problems of carbon fiber composites during the drilling process are analyzed.The 3D biaxial warp knitted carbon fiber composites were drilled and analyzed,and the inlet and outlet morphology analysis and roundness analysis were carried out.Based on the comparative analysis of the experimental results,the high-speed drilling experiment of diamond coated carbide bit is carried out,and the result is analyzed.