A NONLINEAR VISCOELASTIC BUSHING ELEMENT IN MULTIBODY DYNAMICS

This paper presents a formulation for incorporating nonlinear viscoela stic bushing elements into multibody systems. The formulation is based on the assumption that the relaxation function can be expressed as a sum of functions which are nonlinear in deformation and exponentially decreasing in time. These forces can represent elastomeric mounts or b ushings in automotive suspension systems. The numerical implementation of the nonlinear viscoelastic bushing model into a general purpose ri gid multibody dynamics code is described, and an extension of the form ulation is also presented wherein component flexibility is included. M odel validation was performed by comparing experimental data to simula tion results obtained using the nonlinear viscoelastic model and a non linear elastic model. The experimental data were obtained at the Cente r's facilities by testing an automotive lower control arm/bushing syst em, subjected to a simulated road load event. The comparison demonstra tes the better load prediction capability of the viscoelastic bushing model compared to the conventional model.