聚脲单轴压缩应变率效应试验研究

Experimental investigation on strain rate effect of polyurea material under uniaxial compression

采用万能试验机、MTS试验系统和落锤试验机开展了聚脲材料的准静态压缩和动态压缩实验,研究了不同应变率下材料的应力-应变关系,分析其应变率效应,拟合得出应变率与动力增大系数DIF的关系式,对聚脲材料高弹性阶段的本构模型进行了研究。结果表明:准静态条件下聚脲材料的应力-应变曲线可分为普弹性阶段、高弹性阶段和非线性变形阶段。不同应变率下,高弹性阶段的应变有所不同,随应变率变化规律不明显,而应力随应变率的增加而增加。聚脲材料的动力增大系数DIF和相对应变率的对数值呈一次线性关系,且动力增大系数DIF随着应变率的增大而增大。

The quasi-static and dynamic compression experiments of polyurea materials were carried out by using universal testing machine,MTS test system and drop weight testing machine.The stress-strain relationship of the materials at different strain rates was studied,and the strain rate effect was analyzed.The relationship between strain rate and dynamic increase factor(DIF)was obtained and the constitutive model of polyurea material at high elastic stage was studied.The results show that the stress-strain curves of polyurea materials under quasi-static conditions can be divided into general elastic stage,high elastic stage and nonlinear deformation stage.Under different strain rates,the strain of high elastic stage is different,the law of variation with strain rate is not obvious,but the stress increases with the increase of strain rate.Dynamic increase factor(DIF)of polyurea materials and the logarithmic value of relative strain rate show a linear relationship,and the dynamic increase factor(DIF)increases with the increase of strain rate.