Study On Dynamic Mechanical Properties And Simulation Method Of PP–TD20 For Automobile

As the new limiting-value gasoline consuming law promulgated and developed by government,the vehicle weigh reduction process has already became significant research direction of Vehicle Company as the act of energy saving and emission-reduction.The vehicle material also gradually become more energy saving and environment friendly.As vehicle weight reduction material,vehicle plastic applies in wide range,which also is laying much stress on vehicle safety.Therefore,what have widely practical significance are mechanical properties of vehicle plastic and proper material model to describe his mechanical properties.In this paper,firstly,the research test platform is created based on the position on where material PP-TD20 vehicle used and actual working condition in crashing process.Using DIC method the strain fields' information can be determine,and it can be found,this plate is us anisotropic.Through quasi-static and dynamic tensile testes,research tensile fracture behavior of PP-TD20 in 6×10-4S-1 to 4×102 S-1 strain rate range by using DIC measurement.The results show that the elastic modulus,yield stress and flow stress of the material have a large strain rate dependence.Moreover,the strain rate sensitivity is related to the strain rate.Design diverse diameters of cylinder compress specimens,and determine compress engineering stress-strain curve for different strain rates and different dimensions.The results show that the test result is better when the ratio of height to diameter is 0.25.Strain rate 0.001S-1 to 0.1 S-1 range,compressive mechanical properties also exhibit strain rate dependence.Combining DIC method determines the material's engineering stress-strain curve in diverse strain rates in shear stress test,and analyzes how strain rate affect mechanical properties.At the same time,the Johnson-Cook constitutive model is used to characterize the mechanical behavior of PP2 materials at different strain rates.Based on the experimental results,the yield behavior of PP2 material is described by the modified Eyring yield model by Richeton.The results indicate that the yield model can accurately describe the relationship between the tensile yield behavior and strain rate of PP2.The results show that the Johnson-Cook constitutive model can be used to characterize the plastic deformationbehavior of PP2 in the range of our test strain rate.Through analyzing the mechanical properties at different stress find the mechanical properties of material are complex.Based on this research,survey and compare material model,finally select Mat 187 model in Ls-Dyna,which is SAMP-1 model,characterize its mechanical properties.Combining test results,characteristic of SAMP-1 medel,and practical engineering application,build process procedure of inputting model indexes.Build above CAE models for four testes by using commercial pre-process software ANSA,and respectively input SAMP-1 material model built before,simulated the above test.The simulation results match test results well,which means SAMP-1 material model could predict PP-TD20 material mechanical properties well.