| SiCp/Al composite material has excellent physical and mechanical properties,and has been widely used in aircraft parts manufacturing,automobile manufacturing,precision manufacturing,sports equipment and medical equipment and other fields.Due to the extremely high hardness of the Si C particles inside the SiCp/Al composite material,in the process of cutting the SiCp/Al composite material,there are problems such as low cutting efficiency,poor surface quality and many surface defects,which greatly limit the performance of the material.practical application.Ultrasonic Vibration Assisted Cutting(UVAC)is an effective cutting method.Compared with ordinary cutting,it has great advantages in reducing cutting force,improving surface quality and reducing the formation of surface defects.Therefore,,the application of UVAC technology to SiCp/Al composite material is beneficial to the further application of this material.This paper adopts the method of "theoretical modeling-finite element simulation-experimental research",focusing on the cutting process of UVAC cutting SiCp/Al composites,and studies the cutting force and surface defect formation.The main research contents are as follows:(1)Based on the machining characteristics of ultrasonic vibration-assisted cutting in the depth of cut,a theoretical model of cutting force for UVAC cutting SiCp/Al composites was established.Based on the instantaneous undeformed chip thickness model,the theoretical modeling of the cutting force of UVAC cutting SiCp/Al composites is carried out,and the overall modeling process of the cutting force is divided into four parts:modeling of chip forming force,tool-chip contact friction Force modeling,particle fracture force modeling,and ultrasonic impact force modeling were performed using Merchant's theory,two-body sliding and three-body rolling friction theory,Griffith's fracture theory,and momentum theorem,respectively.(2)Using ABAQUS finite element analysis software,a two-dimensional finite element model of UVAC cutting SiCp/Al composites based on "particle-interface-matrix" was established.In the establishment of the finite element model,in order to more accurately simulate the distribution of Si C particles in SiCp/Al composites,a random distribution model of circular particles was established combined with the Python scripting language.Given different material properties of SiCp/Al composites,the Al matrix material constitutive model adopts the Johnson-Cook constitutive model,the Si C particle constitutive model adopts the brittle cracking constitutive model,and the interface constitutive model adopts the cohesive force model.Through simulation,the mechanical laws of UVAC cutting SiCp/Al composites were explored,and the influence laws of vibration parameters(amplitude and frequency)and cutting amount(cutting speed and depth of cut)on cutting force were analyzed to provide theoretical support for subsequent experiments.The formation of surface defects of SiCp/Al composites in UVAC cutting was further studied.The results showed that the surface defects in the UVAC process mainly include three situations: particles rolling and pressing into the matrix,particles breaking and breaking,and particles debonding and pulling out.(3)For the SiCp/Al composite with a volume fraction of 20%,the machinability of the UVAC cutting SiCp/Al composite was studied.Carry out the comparison experiment of ordinary cutting of SiCp/Al composite material and UVAC cutting force,using the single factor experiment method to explore the influence of amplitude,cutting speed and cutting depth on the main cutting force,and compare with the theoretical value of cutting force to verify Validity of theoretical models of cutting forces.By white light interferometer,the surface morphologies of the SiCp/Al composites machined surface under the two processing methods of ordinary cutting and UVAC were compared.The results show that UVAC can help reduce the formation of surface defects and improve the quality of the machined surface. |
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