HYPERELASTIC MODELING OF RUBBER IN COMMERCIAL FINITE ELEMENT SOFTWARE (ANSYS™)

This paper investigates the mechanical behaviour of carbon black rubber at moderate strain (0-25 % engineering strain). Experimental testing in uniaxial, equi-biaxial and planar tension under cyclic quasi-static loading shows strain-induced stress softening, hysteresis and a certain amount of unrecoverable strain. The data obtained from experiments is first simplified assuming a preconditioned perfectly elastic material, and then fitted to popular hyperelastic models in the finite element analysis (FEA) software ANSYS™. A biaxiality test is developed, providing information on the dominant mode of simple strain in the elements of a FE model, and selecting the most appropriate hyperelastic model for the simulation. A two-iteration Preconditioning Method is developed to approximate the softening effect of cyclic loading in a static FEA simulation with hyperelastic material properties. FEA simulations and experimental tests of a cantilevered rubber plate subjected to a bending load at its free end are presented in this paper. The biaxiality test and the preconditioning method are applied to these simulations and agreement with experiment is obtained