Stress analysis of a compressed elastomeric connector spring

When a single elastomeric pad, or block is used as a spring member to generate contact normal forces for a high density interconnection system, it is desirable to have approximately the same amount of normal force for each contact. This paper analyzes the force, or pressure distributions among contacts when an elastomeric block is compressed between two support plates. Simple analytical solutions are derived using a variational calculus approach, in which the fact that the block height, or thickness is much smaller than its length is included to simplify the analyses. The cases of both the rigid and deflectable support plates are studied and the effects of spring design parameters on stress/pressure distributions are discussed. The results show that in the plane strain situation, i.e., for a wide block, the pressure distribution is highly non-uniform and such a design should be avoided. A uniform pressure distribution can be obtained for the plane stress, or the narrow block case when the support plates are sufficiently stiff.