Application of a Novel Method to Identify Multi-axis Joint Properties

Abstract

This article is motivated by the widespread use of shaped elastomeric body mounts that undergo broadband, multi-axis loading; whereas often in application, the principal direction mount properties are measured separately at single frequencies. An inverse method is applied to a new experiment that is constructed with an elastic metal beam end-supported by two elastomeric mounts. Due to a judiciously selected attachment location relative to the neutral axis of the beam as well as the shape of the mount, the in-plane transverse and longitudinal beam motions are found to be coupled. This method utilizes the sensitivity of the beam modal parameters, including natural frequency, mode shapes, and damping ratio, to support properties at each end to identify the multi-axis mount properties. The dynamic stiffness and loss factors of the elastomeric mounts are directly measured in a commercial elastomer test machine and agreement is found between the inverse and direct methods at small displacements. Further, this article helps provide insight into multi-axis properties with new benchmark experiments on off-the-shelf mounts that permit comparison between inverse system and direct component identification methods of the dynamic multi-axis elastomeric mount properties.