AN ANISOTROPIC VISCO-HYPERELASTIC CONSTITUTIVE MODEL FOR CORD-RUBBER COMPOSITES

Based on fiber reinforced continuum mechanics theory, an anisotropic visco-hyperelastic constitutive model for cord-rubber composites was developed to characterize their highly non-linear, strongly anisotropic and strain rate dependent mechanical behaviors under high speed impact or large deformation condition. The unit-volume strain energy function for the visco-hyperelastic model was decomposed into four parts, representing the strain energy from isochoric rubber, the tensile energy from cord elongation, shearing energy from interaction between cord and rubber and viscous potential energy due to viscous characteristics, respectively, which greatly facilitated and simplified the identification of material parameters. By introducing the so called viscous potential energy that could not be neglected under particular loading conditions, the computation accuracy of the model was significantly improved. A simple approach for fitting the parameters was given. Experimental data from literature was used to identify material parameters in the constitutive for a specific cord-rubber composite. The developed model was validated by comparing numerical results with experimental uniaxial tension and bias-tension data under di erent strain rates, demonstrating that the developed constitutive model is highly suitable for characterizing the anisotropic and viscous material behaviors of cord-rubber composites under large deformation. The proposed model is simple, useful and easy for material parameter determination. It provides a theoretical foundation for dynamic finite element analysis of tire in the future.