Nonlinear behavior of elastomeric bearings, I: theory

An “equivalent homogeneous continuum” theory for the nonlinear behavior of a class (flat layers) of elastomeric bearings is developed. The theory should also find application for other layered composites that exhibit the fundamental behavior characteristics of elastomeric bearings. The theory models not only the average behavior of the bearings but also the important edge effects that significantly affect many of the response characteristics of this class of layered solids. For this purpose, in addition to the displacement unknowns, edge effect field variables are introduced into the model. The theory not only permits the calculation of the overall (average) response of bearings, but yields estimates of the local stress and strain states that exist within their individual layers. Both geometric and material nonlinearities are included in the model. While in theory the model could be used to generate analytical solutions for bearing behavior, it is primarily intended as a foundation from which to develop a “composite” finite element analysis for elastomeric bearings. Such a composite analysis is far less expensive than the alternative of using a general purpose finite element program to perform “discrete” analyses of elastomeric bearings.