Study On Turning Process Optimization And Simulation Of SiC Particle Reinforced Aluminum Matrix Composites

Nowadays SiC particle reinforced aluminum matrix composites(SiCp/Al)materials are widely utilized in major industries,including aerospace and automotive industries,sports and medical equipment,electronics,and manufacturing of space aircraft parts,due to high strength to weight ratio,high wear and heat resistance,high modulus and hardness.Due to the existence of reinforced phase SiC particles in SiCp/Al,the tool wear is serious,and it is difficult to obtain high surface quality during the cutting process of SiCp/Al.This research work attempts to analyze the influence of cutting parameters on tool life,surface quality and cutting force in the turning process of SiCp/Al metal matrix composites by simulation and optimization technology to provide support for the selection of cutting parameters in machining SiCp/Al.The main research work of this paper is as follows.Firstly,the second-order response models of tool life,surface quality and cutting force were established by the response surface methodology(RSM).The effects of machining conditions on tool life,surface quality and cutting force were analyzed.Analysis of variance(ANOVA)method was performed to analyze the main effect,interactive effect evaluation and contour plots.Residual analysis was performed using the desirability function and the cutting forces were optimized.The analysis results show that the cutting parameters predicted by response surface method are basically consistent with the experimental results.It has been also found that higher depth of cut,followed by feed rate,will increase the cutting force.Higher cutting speed shows a positive response on reducing the cutting force.Secondly,a SiCp/Al constitutive model considering SiCp,Al matrix and interface layer is established,and the cohesive force model is used to describe the constitutive relationship of the interface layer.On the basis of the cohesive unit,the cohesion model algorithm is described by the custom material subroutine VUMAT.Three different locations of SiC particles relative to the cutting tool path were simulated and the influence of particles in the cutting path on the stress and strain in the simulation process is explored.It is found that the particles bear a large load during the cutting process,and the high stress region is concentrated at the tip of the particle.The failure mode of the particle is mainly brittle fracture when facing the cutting path which is mainly below the cutting path.The particle position above the cutting path is mainly effected by the detachment of the particles from the matrix.The influence of interface layer on the cutting strengthening of SiC particles shows that the interface layer has a significant effect on the stress and strain transfer in the cutting process of composite material.The flexible interface model shows that the enhancement effect does not change significantly with the increase of the interface thickness.The rigid interface model shows that the enhancement effect is significantly better than without the interface.Thirdly,in view of the distribution of the particles in the matrix,this study proposed a two-dimensional particle random distribution algorithm and a FEM model of cutting process for SiCp/Al composite materials.In the ABAQUS interface,a two-dimensional geometric model of particle random distribution was established using the scripting language Python to simulate the different size and different volume fraction of particles.Further,the process of chip formation,surface formation,stress distribution and the change of the cutting force were studied by the simulation model.In the cutting simulation process of SiCp/Al,the influence of particle size distribution,cutting speed,particle volume fraction,particle position,particle size and cutting thickness are considered.The radius of the chip curls gradually increases with the increase of feed rate and cutting speed.The larger the particle size,the smaller the radius of the tool nose,the larger the curl of the chip.High cutting speed reduces the crack propagation and improves the surface quality of the composite material.As the particle size increases,the chip of the composite material gradually changes to band chip.Large SiC particle size ratio will produce internal defects and severe the saw-tooth shape of the chip and cracks which easily penetrates the cutting layer.The experimental results show that the feed rate is the main factor affecting the cutting force fluctuation.Finally,the effectiveness of the finite element model was verified by comparing the cutting force and chip morphology obtained in the experiment data.The influences of cutting speed and feed rate on the cutting force were studied under the condition of keeping the cutting depth constant.The simulation results show that the main cutting force and feed resistance force both increase with the increase of the feed rate,which is consistent with the experimental results.Meanwhile,comparing the simulated cutting force and chip morphology with the experimental results,it is found that the relative errors are less than 10%,which verifies the accuracy of the model.This research provides support for further research on cutting mechanism and cutting process optimization of SiCp/Al.