Stiffness evaluation for components made from natural rubber using Finite Element simulation technique had been discussed in this paper. Conventional method for extraction of stiffness with metallic parts like steel using linear approach is no more valid for rubber (elastomers). Unique properties of elastomers seeks for special material model and capture non-linear behavior. Use of such material models calls for experimental test data with multiple possible directions like uniaxial tension, uniaxial compression, bi-axial tension, planar shear and volumetric test to extract material constants that can capture appropriate deformation modes of the structure. Higher strains also necessitate here to use more complex material models (Ogden, higher order polynomial) to accurately predict the stiffness characteristics.
Special element formulation called hyper-elastic elements is been used to model the rubber parts in FE-Modelling. Further analysis been done using automated contact analysis techniques-friction effects, and the use of contact bodies to handle boundary conditions at an interface. Achieving contact convergence with hyper-elastic elements due to excessive distortion is been addressed with appropriate meshing technique that compensate the deformation pattern.
Multiple powertrain mounts and suspension bushings have been analyzed to validate proposed simulation process. Physical test curves for mounts and bushings show good correlation with CAE simulation results for non-linear load vs deflection curves.