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This paper describes methods for modeling and characterization of hydraulically damped elastomeric mounts. The objective of the work is to be able to fit models to existing parts, describe modifications to current components and to correctly model and specify hydromounts in virtual prototype vehicles. The model used is physically based and begins with the modeling of the basic mechanical properties of the elastomeric element of the mount. It is shown that it is vital to consider the nonlinear physics of the fluid channel, particularly in relation to the hydromechanical characteristics of the elastomeric element. It is shown that the key to the hydraulic damping phenomenon is the internal resonance of the hydraulic fluid in the damping channel on the volumetric stiffness of the fluid cavity in the elastomer. Furthermore, the importance of orifice losses during the pumping of the hydraulic fluid through the channel is shown.

This paper describes a method of characterizing elastomeric mounts that is capable of realistically modeling both triboelastic and viscoelastic phenomena, capturing both amplitude dependent and frequency dependent effects. Triboelastic phenomena are hysteretic force-displacement mechanical properties of the elastomer that are independent of strain-rate, manifesting themselves as a frequency-independent loss angle and an amplitude-dependent stiffness; they differ from conventional viscoelastic effects in which the loss angle is proportional to the frequency: common automotive elastomers often exhibit triboelasticity and viscoelasticity. The method is physics-based and the model parameters are readily fitted to industry standard test and specification methods. At the heart of the method are numerically robust model response functions that are easy to implement as ordinary differential equations in commercial software packages such as MSC-ADAMS™.