Elastomer Models for Virtual Mounting Systems

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™. It is easy to use models that have been fitted to measurements of carry-over components and it is also easy to use the parameters of the model to specify new or modified components, which can be evaluated in a virtual prototype environment before passing on the specifications to a supplier.

The tool described has been developed in-house in a commercial spreadsheet due to the lack of availability of a commercial software tool that addresses the problem of simulating new elastomeric mounts. The only commercial tool (1) known to the authors uses neural network modeling techniques, making it impossible to model a component without a physical sample: the physical approach advocated here allows the modeling of a new component by changing the physical parameters of an existing part or by specifying a new set of parameters. Application examples to real components and systems are given.