EPDM发泡材料应力松弛行为的数值模拟

Simulate and Experimental on Stress Relaxation Behavior of EPDM Foams

利用两种发泡加工工艺,在相同EPDM橡胶基本配方基础上调节发泡剂用量,制备出四种密度不同的发泡材料。通过单轴压缩实验得到了EPDM发泡材料的应力松弛数据,采用理论推演建立的四单元变参数Maxwell模型,模拟EPDM发泡材料的应力松弛行为,拟合结果表明不同发泡程度的橡胶基材,其应力松弛时间和表观松弛强度略有差别,而气体扩散的松弛时间明显较长。拟合所得的比例系数与实测材料的相对密度基本吻合,基材所受的平衡应力随发泡材料相对密度下降而上升。

Based on the same basic formula,the EPDM foams with four different densities were prepared by two kinds of foam technology.Rested on the experimental data of uniaxial compression and stress relaxation,four unit Maxwell model of variation coefficients was adopted to simulate the stress relaxation behavior of EPDM foams with closed-cell.Results showed that the model could be effectively used to fit the stress relaxation of the foams.and the constitutive models can predict the density of EPDM foam.The time of stress relaxation and apparent relaxation strength of different foam material are slightly different,compared with solid EPDM material,the gas diffusion relaxation time was significantly longer.With density decreasing,the balance stress of material increased.