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Date of Award
This dissertation presents a new method to diagnose and analyze structure-borne sound, which enables one to “see through” solid structures and reveal the characteristics of the excitation forces acting behind the structures, including their types, locations, and spectra. Specifically, this method can identify the excitation forces acting behind a vibrating structure by reconstructing the intensity fluxes traveling inside the structure, based on the normal surface velocities and their gradients on the surface that are reconstructed by using the modified HELS method. The input data will consist of the normal surface velocity and the radiated acoustic pressure in the vicinity of the vibrating structure. The output will be the excitation forces acting behind a structure. Experimental validation has been conducted by building a cubic enclosed cavity with a thin panel on top of it. The panel is excited by an unknown source into vibration. Through the comparison of the reconstructed excitation forces with the measured values, it demonstrates that this proposed approach can reconstruct the inner excitation forces with a highly accuracy rate. This methodology establishes the correlations among the excitation forces, structural vibrations, and acoustic radiation from a vibrating structure. The insight gained in this dissertation will help one to acquire a better understanding how structural vibrations and acoustic radiation are related to the excitations, through which one can come up with a more effective strategy to handle various noise and vibration issues.
Lu, Yazhong, "Determining The Characteristics Of The Excitation Forces Acting Inside Structures" (2022). Wayne State University Dissertations. 3640.