Abstract From:
W. Steve Shepard Jr. and Kenneth A. Cunefare, "Sensitivity of Structural Acoustic Response to Attachment Feature Scales," presented at the Symposium on Complexity in Acoustics,
1996 ASME Int. Mech. Eng. Congress and Exposition, November 17-22, 1996, Vol. 22 Pt. 1, pp. 53-60.
When implementing a discrete computational method to predict the vibro-acoustic behavior of a larger structure one must decide how much effort and refinement to expend on modeling smaller attached structural components. In representing these attachments, or features, it is important to know what scales are important with regard to a valid prediction of the system response. To aid in the study of the impact of feature scales, sensitivity relationships for important system variables are developed in this paper. The sensitivity analysis will, for one, consider the change in the radiated power with respect to changes in the scale of an attached mass. These relations are developed analytically and do not require finite difference methods or eigenvalue derivatives. It is shown that computing the sensitivity of the radiated acoustic power only requires evaluating one additional term as all of the other terms are found during the normal course of modeling the system. Furthermore, the terms that include fluid loading on the structure need only be reevaluated when the excitation frequency is changed. It is also noted that the sensitivity relations developed here can easily be used to investigated the effects of modifying a number of structural parameters.
This work studies the impact of changing the feature scale on important system variables. For example, the sensitivity of the surface velocity to changes in an attached mass scale is investigated. The scale is varied by changing the mass density (height), the mass footprint (width), or both. Of course, the latter is required if it is desired to maintain a constant total mass.