密度和应变率对聚苯乙烯泡沫(EPS)准静态压缩力学行为的影响

分别研究了聚苯乙烯泡沫(Expanded polystyrene,简称EPS)在三种不同密度和三种不同加载速率下的无侧限单轴准静态压缩力学行为.结果表明:EPS的压缩与一般多孔材料的压缩特征相似,其应力-应变曲线也分为三阶段(弹性段、塑性屈服平台段及致密段).并验证了聚苯乙烯泡沫(EPS)在线弹性阶段的弹性模量与其密度近似符合二次函数关系;通过对实验结果的拟合得出了EPS的密度与其屈服强度呈线性关系并给出了关系表达式.同时表明:同一密度的EPS在不同加载速率下其线弹性模量基本不变而屈服强度随加载速率的增加而显著增加,其应变率敏感度m值较大且变化显著,EPS表现出明显的应变率效应.

Effects of Density and Strain Rate on Quasi-static Compressive Behavior of EPS

Uniaxial compressive mechanic behaviors of EPS have been studied experimentally in this paper under three different densities and three different strain rates respectively.It has been found that the compressive stress-strain curves of EPS,like other foam-materials,also have three deforming regions(elastic region,plastic collapsing region and densification region).The result of experiment demonstrate that the relationship between EPS' linear elastic modulus and its density is a second power polynomial function.Based on the experimental results,we gained that the relation of density and yield strength of EPS is linear and gave the function.The same density EPS has about same linear elastic modulus under different strain rates but yield strength obviously increases with the increasing of strain rates,and the values of strain rate sensitivity(m) are high and vary greatly,EPS have obvious strain rate effect.