Nonlinear finite element analysis of rubber bush with large form factor

In this study nonlinear finite element analysis is used to investigate the static deflection behavior of rubber bush, focusing on the effect of material compressibility on numerical results. The hyperelastic material is modeled as the 2nd order Ogden function, the parameters of which are obtained from uni-axial, planar and volumetric tests. Numerical analysis shows for the rubber bush with larger form factor the results are very sensitive to volumetric test data, which hence should be prepared with greater accuracy in situations where the pressure in the body is much higher compared to the shear stress. Even in some cases, the analysis without volumetric data included results better than the one using all experimental data available. For the purpose of quantifying the need for more accurate volumetric test data for a particular bush shape, conventional definition of the form factor can no longer be used and a new criterion is successfully proposed using average strain energy density from a preliminary linear finite element analysis.