Validation of a four-pole modelling for coupling loss factor between two plates connected via vibration isolators under mechanical excitation

摘要

A hybrid Experimental-SEA (Statistical Energy Analysis) model has been developed forpredicting structural transmission through a two wall system connected via aircraftvibration isolators. The system is composed of two isotropic plates with critical frequenciesaround 3750 Hz and 6000 Hz, coupled at 6 locations via elastomeric mounts. The plates aremechanically excited by a point force at random positions over the frequency range from100 Hz to 10000 Hz. The structural coupling loss factors (CLF) between plates are obtainedthrough a four-pole modelling of the vibration isolators, which integrates measuredfrequency dependent mount stiffness. The modelled CLFs are then compared withmeasurements using an experimental SEA approach. Finally, the space-averaged quadraticvelocities of the plates are calculated using the hybrid model and compared withexperiments. Results show a good correlation between predicted and measured CLFs butfurther refinement is needed in order to account for radiation coupling near the criticalfrequencies of the plates.