| Pistons play an important role in engine,and they need to withstand a certain degree of thermo-mechanical fatigue load during the working phase.Due to the severe changes in the working environment,the processing and manufacturing of pistons are facing more and more demands.However,ZL109 aluminum alloy,a commonly used material for pistons,has the disadvantages of severe tool wear,prone to build-up chips,and large deformation after processing,which restricts the processing accuracy and service life of the piston.In this paper,a combination of test and simulation is used to study the key process of the piston-the outer circle and the bore of the pin,to optimize the cutting parameter combination of the above two processes with the goal of improving the surface quality of the piston after machining.Initially,the mechanical properties of ZL109 aluminum alloy under various tensile speeds,temperatures,and various stress conditions were tested,and the corresponding model parameters of the material were configured.The results show that the strain rate strengthening effect occurs under quasi-static conditions of ZL109 aluminum alloy.If the strain rate gradually increases,the yield limit will increase accordingly,and the tensile limit will show the phenomenon of decreasing first and then increasing;if it is in a high tensile speed,the material will yield when the stress increases to a certain value,but the overall value of the curve at each strain rate is not much different;after 200?,the yield strength of the material will weaken to a certain extent,but the plastic will enhanced;the material's J-C constitutive model parameters-A is 323.25 MPa,B is 301.54 MPa,n is 0.5,C is 0.00965,m is 0.624;the J-C damage model parameters of this material-D1 is 0.351,D2 is 2.087,D3 Is 5.222,D4 is-0.0147,and D5 is 0.032.ABAQUS software was uesd to establish a two-dimensional turning simulation modeling,and then the corresponding analysis of the actual distribution of residual stress,equivalent plastic strain and numerical values to verify the reliability of the established model.At the same time the obtained material model parameters was inputed,and the cutting force and cutting temperature of the simulation output are compared with the experimental data of turning under the same conditions to confirm the accuracy of the material parameters.Furthermore,on the basis of the previous model,multiple analysis steps are added to build a multi-step cutting simulation model.And analyze the influence of cutting amount on various measuring indexes during cutting and after cutting,and get the best combination:v=340 m/min,f=0.1 mm/r,and ap=0.1 mm.A boring pin hole experiment was carried out on a three-axis vertical machining center,the influence of cutting amount on the surface morphology and residual stress after boring finishing was analyzed,and the most suitable combination for boring finishing was found,which was set as:cutting speed v=75 m/min,feed amount f=0.04 mm/r,and cutting depth ap=0.12 mmThe secondary development of the plug-in program of the ABAQUS finite element software has been completed by using Python language,and some settings of the pre-processing process are parameterized into a unified GUI interface.The user only needs to enter the corresponding number in the interface and a series of pre-processing operations such as modeling,setting material properties,meshing,and setting friction properties will be completed automatically,which greatly shortened the time of the optimization parameters of the piston turning process and provided references for secondary development in other simulation fields. |
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