Modeling of Nonlinear Elastomeric Mounts. Part 1: Dynamic Testing and Parameter Identification 2001-01-0042
A methodology for modeling elastomeric mounts as nonlinear lumped parameter models is discussed. A key feature of this methodology is that it integrates dynamic test results under different conditions into the model. The first step is to model the mount as a linear model that is simple but reproduces accurately results from dynamic tests under small excitations. Frequency Response Functions (FRF) enables systematic calculation of the parameters for the model. Under more realistic excitation, the mount exhibits non-linearity, which is investigated in the next step. For nonlinear structures, a simple and intuitive method is to use time-domain force-displacement (F-x) curves.
Experiments to obtain the F-x curves involve controlling the displacement excitation and measuring the induced forces. From the F-x curves, stiffness and damping parameters are obtained with an optimization technique.
The paper also discusses the variation of stiffness and damping parameters with mean force and amplitude. Analytical expressions for spring constants and damping factor are obtained as functions of preload, amplitude and velocity.
This paper is the first of two papers describing the research effort on the elastomeric mount. The companion paper will discuss numerical modeling to validate and improve the relationship between the experiment results and the analytical model.