Tensile Test And Numerical Simulation Research On PC And PMMA Two Kinds Of Polymer Materials

This paper using SHIMADZU testing machine to do the tensile test with engineering plastic PC (polycarbonate) and PMMA (poly methyl methacrylate) materials at different temperatures and different rates of quasi-static. Polycarbonate test temperatures were 30℃, 60℃, 90℃, 120℃, tensile rate 2.5mm/min and 7.5mm/min, the corresponding strain rate were 0.00033 s-1and 0.001 s-1. PMMA test temperature were 30℃, 45℃, 60℃, tensile rate 1.25mm/min and 5mm/min, the corresponding strain rate were 0.0002 s-1 and 0.0008 s-1. The results showed that: polycarbonate and poly(methyl methacrylate) on mechanical properties has obvious correlation between strain rate and temperature, when the strain rate increased, the yield stress increases and elongation decreases, when the temperature rise high, the yield stress decreases, the elongation at break increases. And the strain rate and temperature have the equivalent effect on the mechanic properties of PC and PMMA, while higher temperature and the same time strain rate increases can get the same stress - strain curve.Through the analysis of test data and image, we select the appropriate constitutive model (DSGZ constitutive model) to simulate the test. Firstly, determine the model constants of the test data obtained in the DSGZ constitutive equation of PC material and PMMA material. In order to make the model more coincide with the test, the DSGZ constitutive equations of PC material has been improved and determined the improved DSGZ constitutive equation of PC material. Secondly, customize the secondary development of the DSGZ constitutive model in ANSYS software by FORTRAN language. In other words, we write the improved DSGZ constitutive model of PC material and the DSGZ constitutive model of PMMA material in ANSYS in the user material subroutine. Then, verified the user material subroutine with the numerical simulation of tensile on element. Finally, do tensile numerical simulation about PC material and PMMA material according the established user material subroutine in ANSYS software to obtain tensile stress - strain curves. From comparing the simulation and experimental tensile stress– strain curves, we can see that is suitable for both. Further verify the correctness of the subroutine.In application of the user material subroutine that we have already written, we carried out an numerical simulation in which we put the street lampshade in a condition under 30 degree and in the same time, the loading putting on the street lampshade is different. So we get the Max stress value and Min stress value that the street lampshade in different wind velocity thereby we proved the practical character of the material subroutine for further.