多孔硅橡胶有限变形的粘弹性行为

针对孔隙度较大(孔隙度大于50%)的硅橡胶材料在有限变形时的粘弹性行为,从建立描述材料粘弹性特征的松弛函数和变形特征的应变能函数出发,提出了适合多孔隙、可压硅橡胶材料的非线性粘弹性力学行为的本构关系,松弛函数和应变能函数可解耦为等容和体积变形两部分,并引入了拟时间的概念来反映变形对材料特征时间的影响.利用硅橡胶材料的单轴压缩松弛实验与材料模型进行了对比,讨论了多孔硅橡胶的等容变形和体积变形对应力松弛的影响.

VISCOELASTIC BEHAVIORS OF POROUS SILICONE RUBBERS UNDER FINITE DEFORMATION

Dealed with viscoelastic behaviors of porous silicone rubbers with high porosity under finite deformation. It proceeded from building up relaxation function for viscoelastic property and strain energy function for deformation character, respectively, a constitutive relation for nonlinear viscoelasticity of porous compressible silicone rubbers was further developed. The relaxation function and strain energy function were additively split into isochoric and volumetric parts whereas the concept of peusdo-time was introduced to describe the effect of deformation on material characteristic time. A comparison of theoretical model was carried out with uniaxial compression relaxation experiments of the rubber. The effects of isochoric and volumetric deformation on stress relaxation were then discussed.