MULTIDIMENSIONAL MOUNT EFFECTIVENESS FOR VIBRATION ISOLATION

A method is presented for predicting the performance of multiple mount passive isolation systems. Performance is expressed in terms of a mou nt effectiveness matrix which relates the structure vibration in an is olated system to the structure vibration in an unisolated, or hard-mou nted system. Frequency response functions of the engine, isolator, and structure are used to construct the effectiveness matrix at each freq uency of interest. Effectiveness matrix. expressions are derived for a mounting system connected at multiple points by massless isolators. I solator design guidelines are developed for the single and multiple is olator mounting systems. It is shown that a multiple isolator mounting system is effective when the maximum singular value of the isolator i mpedance matrix is less than the minimum singular value of the equival ent engine and structure impedance matrix. An analytical example shows that the traditional single isolator expression for mount performance does not provide an accurate metric of mount performance for highly c oupled multiple mount systems. Results on a simple experiment show goo d agreement between the predicted and measured structural response usi ng the mount effectiveness.