开孔泡沫塑料的应力松弛问题

开孔泡沫塑料具有良好的能量吸收和缓冲性能, 在工程中得到了广泛的应用, 对其粘弹性行为进行研究具有重要的意义.基于Lederman模型,应用三参数标准线性固体模型考虑基体的粘弹性性能,对开孔泡沫塑料的应力松弛行为进行了研究,并讨论了所加应变载荷、结构参数和泊松比对应力松弛曲线的影响.结果表明:应力松弛曲线对泊松比是不敏感的,并且,应变载荷的增加和相对密度的提高会使应力松弛变得更加明显,但应力响应的初始值和终值的比却不随应变载荷的提高而变化.

Stress relaxation of open-cell foamed plastics

Open cell foamed plastics have better energy absorption characteristics and better cushioning properties so that they are extensively used in engineering areas. Thus, their visco-elastic behavior has attracted the most people attentions. Based on the Lederman model, the stress relaxation of open-cell foamedplastics was investigated by using the model of standard linear solid to consider the visco-elastic behavior of matrix. The effect of strain loading, structuralparameter and Poisson’s ratio on the stress relaxation curve of open-cell foamed plastics was discussed at the same time. The results show that the stress relaxation curves are not sensitive to Poisson’s ratio and the increase of strain loading or relative density will make the stress relaxation more significant. However, the ratio of initial and final value for stress response does not change with the increase of strain loading. All the above conclusions obtained are very important for overall understanding the mechanical behavior of open cell foamed plastics.