ASA 125th Meeting Ottawa 1993 May

4pSA1. External system modeling: An approach to minimizing vibroacoustic model sizes for design evaluation.

B. K. Gardner

J. S. Bolton

1077 Ray W. Herrick Lab., School of Mech. Eng., Purdue Univ., West Lafayette, IN 47097-1077

Numerical vibroacoustical models of dynamic systems can easily become so large that they are impractical when used to analyze alternative system designs. Hence, when evaluating designs for single sub-components of a large system, the analysis is often limited either to that sub-component combined with idealized boundary conditions, or to the sub-component and a small portion of the rest of the system (i.e., the exterior system). In this paper a technique, based on the receptance method, is presented that allows a model of the complete system to be replaced by a complete model of the sub-component combined with a minimal model of the exterior system. Thus the in situ dynamics of a particular sub-component may be evaluated without having to solve the entire system. This approach allows sub-component designs to be assessed quickly so that the merits of many potential designs may be evaluated. The assumptions required by this approach are: steady-state conditions, linearity, and that the forces acting on the external system are unaffected by changes in the sub-component. The external system model may be obtained either numerically or experimentally. The proposed approach is demonstrated here analytically using a system of beam-like elements.