中高应变率下EPS泡沫的冲击压缩实验

Impact Compression Experiment for EPS Foam under Mid-high Strain Rate

用SHPB装置对三种密度的发泡聚苯乙烯(Expanded Polystyrene,EPS)材料进行了从300/s至1400/s共五个中高应变率下的冲击压缩实验。实验中采用波分离技术有效延长应力-应变曲线的测量范围,并简要介绍了其原理和具体实施办法。所有应变率下均获得了含有弹性段、平台屈服段和压实段完整三阶段的应力-应变曲线。曲线的重复性较好,应变率基本恒定。实验结果表明,相同密度EPS泡沫应力-应变曲线的屈服平台段长度随应变率的增加而增加,且趋于平缓。在相近应变率下,随EPS泡沫的密度增加,屈服应力增加,而变形及吸能能力减弱。

Impact compression experiment was carried by using Split Hopkinson Pressure Bar（SHPB） for expanded polystyrene（EPS） foams with three different densities and under five different mid-high strain rates ranging from 300/s to 1400/s.In experiment,wave separation technique was adopted to extend the measuring range of stress-strain curve.Principle and implement of this method is introduced briefly in this paper.Integrated three-stage stress-strain curve including elastic region,plastic collapsing region and densification region was all obtained under different strain rates.Curves have better repeatability and strain rate is basically kept constant.Experimental results show that for EPS foam with the same density,the length of plastic collapsing region in a stress-strain curve increases and the curve form flattens along with strain rate increase.Under similar strain rate,the yield stress increases with the increasing of EPS foam density,but the ability of deformation and energy absorption are weakened.