Dynamic Characterization of an Elastomer Pad for Vibration Isolation

Elastomeric pads are widely used in the aerospace and automobile industry for vibration isolation of various systems. The dynamic properties of elastomers show a strong dependency on frequency and temperature. This study was intended to obtain the frequency dependent dynamic properties, namely, dynamic stiffness and loss factor, of an aerospace grade nitrile base elastomeric test specimen through experimental techniques. The test specimen was prepared similar to a single degree of freedom system by bonding a rectangular steel block with the elastomer pad. The dynamic stiffness and the loss factor of the test specimen were obtained from the frequency response function through an electrodynamic shaker experiment. The values of the dynamic stiffness and the loss factor showed an increasing trend with respect to the frequency. To capture the properties in all the three coordinate axes, the specimen was excited in respective directions and the responses were measured. This article also presents the finite element approach for modeling the elastomer as hyperelastic model to identify its modal parameters such as natural frequencies and the corresponding modeshapes. The uni-axial stress–strain data of the elastomer pad was used to generate the hyperelastic material model. The results from the finite element analysis were validated by the impact hammer experiment.