一种介电型电活性聚合物材料的非线性超弹性模型

介电型电活性聚合物(Electroactive polymer,EAP)材料的应力应变本构模型是进行EAP驱动器设计和优化的基础。提出一种由非线性弹簧组成的、具有空间网状结构的EAP膜超弹性模型,基于能量法推导出其应力变形关系式,并揭示该模型与Ogden模型之间的关系。采用单轴、等双轴拉伸试验分别对相关模型参数进行拟合,利用该结果对等双轴、单轴拉伸的受力进行预测和对比分析。根据不同条件拟合出的材料参数进行试验预测时,其结果与实际值存在一定差异,提出对单轴、等双轴拉伸试验数据进行综合拟合的方法。采用综合拟合方法后模型分析精度得到很大提高。分析结果表明,3参数的非线性超弹性模型能较准确描述两种试验条件下的EAP膜应力变形关系,模型参数的拟合数据宜选与其工作条件相近的试验方法获取。

A Nonlinear Hyperelastic Model for Dielectric Electroactive Polymer Materials

The stress-strain constitutive model for dielectric electroactive polymer (EAP) films is the basis for the design and optimization of EAP actuators. A nonlinear hyperelastic model of EAP film with a space network structure is proposed, which is composed of nonlinear springs. Based on the energy method, the equations of stress and deformation are derived, and the relationship between the hyperelastic model and Ogden model is also revealed. The model parameters are fitted through uniaxial and equi-biaxial experiment data, and then the models also used to forecast the tensile stresses of equi-biaxial and uniaxial tests, and the results are compared and analyzed. There exist discrepancies between the predicted results and test data when using the models to forecast tests which parameters fitted under different experiment conditions. Comprehensive fitting method is presented for uniaxial and biaxial tensile experiment data, and then the analysis precision greatly improved. The results show that, under two experiment conditions, the 3-parameters nonlinear hyperelastic model can accurately describe the relationship of stress and displacement of EAP films, and the model parameters should acquire through the experiments similar to work conditions.