In the paper an orthotropic hyperelastic constitutive model is presented which can be applied to numerical simulation for the response of biological soft tissue and of the nonlinear anisotropic hyperelastic material of the cylindrical air-spring shell used in vibroisolation of driver's seat. | Vietnam Journal of Mechanics, VAST, Vol. 27, No. 2 (2005), pp. 118 - 128 IDENTIFICATION PARA METERS OF M ATERIAL MODEL AND LARGE DEFORMATION ANALYSIS OF INFLATED AIR-SPRING SHELL MADE OF RUBBER-TEXTILE CORD COMPOSITE TRAN Huu NAM Hanoi University of Technology Abstract. In the paper an orthotropic hyperelastic constitutive model is presented which can be applied to numerical simulation for the response of biological soft tissue and of the nonlinear anisotropic hyperelastic material of the cylindrical air-spring shell used in vibroisolation of driver's seat. The parameters of strain energy function of the proposed constitutive model are fitted to the experimental results by the nonlinear least squares method. The deformation of the inflated cylindrical air-spring shell is calculated by solving the system of five first-order ordinary differential equations with the material constitutive law and proper boundary conditions. Numerical results of principal stretches and deformed profiles of the inflated cylindrical air-spring shell obtained by numerical deformation analysis are compared with experimental ones. Key words: constitutive model, rubber-textile cord composite, air-spring shell 1. INTRODUCTION The composite materials created of rubber matrix reinforced by textile cords is called rubber-textile cord composites. Air-springs form an example of layered multiphase flexible composite structures that consist of rubbery matrix and stiff reinforcement made of textile cords. The high modulus, low elongation cords carry most of the load, and the low modulus, high elongation rubber matrix preserves the integrity of the composite and transfers the load. The primary objective of this type composite is to withstand large deformation and fatigue loading while providing high load carrying capacity. Recently, classical phenomenological constitutive equations for rubber-like solids, such as Mooney- Rivlin, Neo-Hookean or Ogden models (Beatty, 1987; Holzapfel et al, 2000 ; Bonet
