Abstract
Rubber-like materials have strong nonlinearities in dynamic and static stiffness and damping characteristics. To confirm all of the nonlinearities of rubber material, a large number of tests must be carried out. Therefore, the evaluation method with which stiffness and damping characteristics including several nonlinearities of rubber element can be estimated by a few kinds of material tests is greatly useful. The purpose of this study is to establish an evaluation method in which the nonlinearities of rubber-like material caused by loads applied in both the shear and compression directions are taken into consideration. As the first step of this study, the material stretch test, the static load test and the FEM analysis were carried out to verify the nonlinear characteristics of the static stiffness caused by loads applied in both the compression and shear directions. It was verified that the static compression stiffness dependency on the initial shear deformation and the static shear stiffness dependency on the initial compression deformation can be expressed by the FEM analysis. To accurately express the force-displacement relationship, the estimation methods of a strain level which dominates the stiffness of a rubber isolator should be investigated.
