Analysis of Negative Stiffness Devices with Application to Vehicle Seat Suspensions

Abstract

This research is motivated by some vehicle seat suspension designs that claim improved vibration isolation and motion control through use of snap-through devices. The geometric nonlinearity concept can be used to create negative spring stiffness and such mechanism are achieved by either a particular mechanism design or via slender beam structures. This research studies both concepts, the first one through an analytical model and the second one using a nonlinear finite element code. The nonlinear spring models are approximated via a cubic polynomial stiffness term (hardening type). Typical transient response of a single degree of freedom nonlinear system model is studied when subjected to initial conditions, ramp input, or a base excitation profile (over a limited time duration).