ASA 127th Meeting M.I.T. 1994 June 6-10

4pSAa6. Modal approach and statistical energy analysis of plate structures subject to point excitations.

B. M. Gibbs

A. T. Moorhouse

Acoust. Res. Unit, School of Architecture and Bldg. Eng., Univ. of Liverpool, P. O. Box 147, Liverpool L69 3BX, UK

A global mode approach to the bending vibration of structures composed of thin rectangular plates is described and applied to a T combination of five plates under point excitation. The boundary conditions at the edges, including the junctions between the plates, allow rotation only but a complex rotational stiffness can be incorporated to model conditions ranging continuously from the simply supported to the rigidly clamped condition at the non coupled edges. Predicted point and transfer mobilities on the same plate and across one or more junctions give good agreement with scale model measurement. The method of analysis can be used in the frequency region of high modal overlap where statistical energy analysis applies and predicted spatial average bending energies, obtained by both methods, compare favorably. Results also compare favorably with scale model measurement. The computational time for the modal approach is not long and a study is proposed involving a parametric survey where SEA terms can be redefined and an estimate made of their sensitivity to variations in frequency, excitation, dimension and material properties.