一种改进的Yeoh超弹性材料本构模型

AN IMPROVED YEOH CONSTITUTIVE MODEL FOR HYPERELASTIC MATERIAL

橡胶通常被看作一种不可压缩各向同性的超弹性材料,其本构模型通常用应变能密度方程表示。针对Yeoh模型偏软的特性,该文提出了一种改进的Yeoh超弹性材料本构模型。基于连续介质力学大变形理论,给出了改进的Yeoh模型在三种特殊变形模式下的应力-应变关系,并与原有的Yeoh模型和实验数据进行了对比。结果表明:改进的Yeoh模型在保持Yeoh模型体现反"S"形应力-应变关系的前提下,有效地克服了Yeoh模型在预测等双轴拉伸曲线时"偏软"的特性。在较大的应变范围内能够同时准确地预测单轴、平面和等双轴拉伸-压缩的应力-应变关系,具有较大的工程应用价值。

Rubber is generally regarded as incompressible, isotropic, and hyperelastic material whose constitutive model is usually described in terms of strain energy density functions. An improved Yeoh model for hyperelastic material is proposed in this paper to improve the ‘soft＇ property of the Yeoh model. The strain-stress relations of three special deformation modes for the proposed model are presented based on the large deformation theory of continuum mechanics, and compared with those obtained by the original Yeoh model and by the experiment data. It is found that： the improved Yeoh model represents an inversed ＂S＂ shape of the strain-stress relation, and effectively overcomes the ‘soft＇ property of Yeoh model when predicting the strain-stress curve of equibiaxial extension at the same time. The proposed model precisely predicts the strain-stress relations of uniaxial, planar and equibiaxial tension-compression in a large strain range and has great values in engineering application.