不同加载应变率下有机玻璃的压缩破坏与力学行为

Compression Failure and Mechanics Behavior of PMMA under Different Loading Strain Rates

对有机玻璃试件进行准静态和动态压缩试验,研究加载应变率对有机玻璃材料力学性能的影响,分析不同加载应变率下有机玻璃材料的微观损伤破坏模式。通过简化黏弹性本构方程拟合出适用于有机玻璃材料的黏弹性模型参数,并与试验结果进行比较。结果表明:在准静态加载条件下,有机玻璃表现为延性破坏,在动态加载条件下则表现为脆性破坏;随着加载应变率的提高,有机玻璃的流动应力明显增加,且动态加载条件下的峰值应力增加速率高于准静态。

The uniaxial quais-static and dynamic compression tests of PMMA in a large range of strain rate were completed to investi- gate the effect of strain rate on the mechanical properties of PMMA. The microscopic damage modes of deformed PMMA pieces from different loading strain rates were analyzed by SEM. The parameters of viscoelastic constitutive model for PMMA were fitted by simplify- ing known equation, and the fitted curves from the viscoelastic constitutive model were compared with the experiment data. The results indicate that the ductile failure is shown in the quais-static loading mode and the brittle failure is shown in the dynamic loading mode. The flow stress of PMMA obviously is increased along with the rising of the strain rate. In the dynamic loading mode, the rising rate of peak stress is obviously higher than that in the quais-static loading mode.