Al2O3陶瓷材料应变率相关的动态本构关系研究

采用改进的SHPB实验方法对Al2O3陶瓷的动态力学性能进行了研究,得到了材料在较高应变率范围内的动态应力应变曲线。结果表明,Al2O3陶瓷为弹脆性材料,其动态应力应变呈非线性关系,在较高的应变率范围内,陶瓷材料的动态应力应变关系是应变率相关的;材料的初始弹性模量、破坏应力、破坏应变值随应变率的增大而增大。基于损伤力学的基本理论,给出了Al2O3陶瓷的一维损伤型线性弹脆性本构模型。根据SHPB实验结果确定模型中的参数,得到了Al2O3陶瓷应变率相关的损伤型动态本构方程。

A study on the strain-rate dependent dynamic constitutive equation of Al2O3 ceramics

The dynamic mechanical properties of Al_(2)O_(3) ceramics have been investigated in this paper using the classical and the improved techniques of Split Hopkinson Pressure Bar (SHPB). It is shown that the tested ceramic is nonlinear elastic-brittle material and insensitive to strain-rates in lower ranges but sensitive in higher ranges. The dynamic elasticity modulus and the dynamic compressive strength of the ceramic increase with the strain rate increasing. Based on the theory of damage mechanics, a uniaxial nonlinear elastic-brittle damage-modified constitutive model is proposed here. The parameters of this model for the Al_(2)O_(3 ) ceramic were obtained by fitting the SHPB test data. It is a strain-rate dependent damage-modified nonlinear elastic constitutive equation of Al_(2)O_(3 ) ceramics.