Stress Response of a Rubber Block under Vertical Loading

Abstract

Rubber blocks (or springs) are structural components widely used in many applications. The design characteristics of a rubber block (or spring) under vertical loading are an apparent modulus (or compression modulus) and normal and shear stresses on the contact surfaces. The problem of a rubber block bonded to two rigid plates has been solved using various approaches. In this study, improved approximate solutions for rectangular blocks in plane strain and for axisymmetric disks are derived using a combination of an energy method and linear elasticity approach when the rubber is treated as a linear elastic incompressible material. The closed-form results are compared with previous results for the apparent modulus and contact stress distributions. Similarly, the problem of a rubber block with a surface bonded to a rigid plate while another surface is in contact with a zero frictional rigid plate is also solved using the same method. Finite-element analysis and experiment results for axisymmetric disks of several shape factors ranging from 1 to 6 are compared for validation of the analytical results for both contact conditions.