ACOUSTIC RADIATION PREDICTION OF A COMPRESSOR HOUSING FROM 3-DIMENSIONAL EXPERIMENTAL SPATIAL DYNAMICS MODELING

An application of experimental spatial dynamics modeling (ESDM) is dem onstrated for predicting the sound radiation from a vibrating structur e based on experimental velocity response data. A scanning laser Doppl er vibrometer (LDV) is used to measure velocity at thousands of locati ons on the surface of the radiating structure. Velocity measurements a re acquired from multiple laser positions where the position and orien tation of the LDV relative to the structure are determined. A weighted least-squares discrete finite element formulation is used to solve fo r the complex-valued continuous three-dimensional velocity response fi eld on the surface of the structure from the experimental data for a s ingle frequency. The velocity field solution on the surface provides t he necessary boundary values input into a finite element/boundary elem ent acoustic code for predicting acoustic radiation. This experimental -numerical noise prediction technique was demonstrated on the housing of an operational reciprocating Freon compressor. The technique was ve rified by comparing measured and predicted acoustic responses, This is first time an experimental three-dimensional spatial dynamics model h as been linked directly to the acoustic analysis of complex structures . The capability to make in-the-field vibration measurements, solve fo r the complex-valued continuous thr ee-dimensional velocity response f ield, and predict the acoustic response from the same test is a novel approach and a major contribution of this work. (C) 1996 Elsevier Scie nce Ltd.