硬质聚氨酯泡沫塑料本构关系的研究

STUDY OF THE CONSTITUTIVE RELATIONSHIP OF RIGID POLYURETHANE FOAM 1)

介绍用大尺寸分离式Ｈｏｐｋｉｎｓｏｎ压杆对四种密度的硬质聚氨酯泡沫塑料进行高应变率实验，完整地给出了这种材料在１０３／ｓ高应变率下的包括弹性区、屈服区和致密区变形全过程的动态应力应变曲线，并提出了包括应力、应变、应变率和密度等参量的本构关系．

Rigid Polyurethane Foam is a material with cellular structure. It has excellent properties for cushioning and energy absorbing and is used in packaging and protective padding. So it is important to study its dynamic mechanical behaviour and to propose its constitutive relation including stress, strain, strain rate and density. In this paper, the high strain rate experiment of rigid polyurethane foam of four kinds of density by Split Hopkinson Pressure Bar was introduced, and the strain rate is 1 000/s, 1 500/s, 2 000/s and 2 500/s respectively. The four compressive stress strain curves have the same shape characterized by three distinct regions: initial linear elasticity, a stress plateau and a final region of steeply rising stress corresponding to densification. According to the experimental results, including quasi static experimental results, a fitted constitutive relationship is σ=ρ ρ 0 A·ε B(ρ ρ 0 -1) · 1+C· lg 0 ·6 i=1 A iε i