On the Dynamic Compressive Mechanical Properties and Strain Rate Related Constitutive Model of PMMA Material
PMMA材料的动态压缩力学特性及应变率相关本构模型研究

In order to investigate the effect of loading strain rate on the mechanical properties of PMMA, uniaxial compression test of PMMA in a large strain rate range was performed by using INSTRON universal testing machine and split Hopkinson pressure bar system (SHPB). Microstructure of deformed samples was microscopically observed based on SEM technique, microscopic damage and failure mode of PMMA at different loading strain rates are the focus of analysis. Results show that the flow stress of PMMA increases obviously with the increase of loading rate; under high strain rate loading condition, the strain rate sensitivity of peak stress is obviously higher than that in quasi-static region; under quasi-static loading condition, PMMA sample shows obvious ductile failure characteristics, while under dynamic loading condition, it presents brittle failure characteristics. Finally, PMMA ZWT visco-elastic constitutive model parameters were fitted, which show good coincide with experimental data. So it indicates that this constitutive model can better describe stress-strain relation of PMMA in a wider range of strain rate.