Coupling loss factor estimation for plates joined at a point: Analysis and experiment.

Coupling loss factors for two lightly damped plates joined at a point, but otherwise free to respond in lateral vibration, have been studied both analytically and experimentally. This study forms the basis for on-going estimations of the transient coupling loss factors of the same system. Statistical energy analysis (using VA ONE) and the finite element method (using NASTRAN) have been used to predict the coupling loss factors. The finite element predictions are based on the averaged responses for a range of boundary conditions on the plates, essentially a “pseudo-statistical” approach. Experimentally, two techniques have been used. First, following the approach by Lai and Soom, a force transducer has been used to measure the force between the plates as it is used to attach them. Simultaneously, the kinetic energies in the two plates are measured by three accelerometers attached to each plate during both transient and persistent excitations of the plates, one at a time. The coupling loss factors are estimated by balancing the transmitted energies with the kinetic energies in the two plates. Then, the coupling loss factors were assessed by a more “traditional” approach, namely, balancing the power input to a plate with the energies of the plates. The estimations from these four approaches compare as well as may be expected for these lightly damped plates.