介电弹性体力学松弛的试验与理论研究

Experimental and theoretical study on mechanical relaxation of dielectric elastomer

针对介电弹性体的粘弹性应力松弛现象,通过单轴拉伸的应力松弛试验研究了材料应力在不同预拉伸率下的时变特征,建立了材料基于Prony级数的准线性粘弹性模型。研究结果表明:通过理论计算和实验结果的对比验证了模型的准确性,预拉伸率是影响介电弹性体薄膜应力松弛曲线的重要因素,基于二阶Prony级数的准线性粘弹性模型能够有效模拟介电弹性体薄膜预拉伸率在[2,6]区间内的非线性力学松弛特性,而且与实验值拟合度较高;在预拉伸率为4,400s条件下,介电弹性体薄膜的应力达到0.126MPa。

Focusing on the phenomenon of viscoelastic stress relaxation of dielectric elastomer,uniaxial tensile stress relaxation experiment under different pre-stretches was conducted to explore the time-varying characteristics of material stress.Besides,the quasi-linear viscoelastic model based on prony series wa established,and its accuracy was verified by comparison between theoretical calculation and experimental statistics.The results indicated that pre-stretch was a key factor to determine the stress relaxation curve of dielectric elastomer and the quasi-linear viscoelastic model based on second-order prony series can describe the nonlinear mechanical relaxation characteristics effectively under the pre-stretch range of [2,6].