Efficiency Of Annularly Distributed Moment And Force Excitation Regarding Structural Acoustic Power Transmission To Plate-like Structures

✍ Scribed by B.A.T. Petersson

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 488 KB
• Volume: 176
• Category: Article
• ISSN: 0022-460X
• DOI: 10.1006/jsvi.1994.1403

✦ Synopsis

A theoretical analysis of various distributed excitations is undertaken. The distributed excitations correspond to the integrated stresses at the interface between a built-up superstructure and a plate-like recipient for the vibratory energy. The analysis is concentrated on the efficiency of annularly distributed excitations with respect to the transmission of structural acoustic power. General force and moment distributions are assumed and the elementary, low order excitation modes are examined explicitly. Comparisons are made for, on one hand, distributions corresponding to primary, lateral and transverse force excitations of the superstructure and, on the other, moment and force. It is found that for the range in which the wavelength of the recipient is much longer than the typical cross-sectional dimension of the superstructure or primary excited section thereofHelmholtz numbers below unity-point quantities of the recipient, such as the ordinary point mobilities, apply. Hence, the transmission process is dominated by the uniformly distributed normal force. It is also found that, in the same range, the first order rather than the zero order excitation mode with respect to a distributed moment predominates. For Helmholtz numbers above unity, however, the distributed moment rapidly grows in importance, and irrespective of excitation mode. Hence, for a large-and with respect to engineering practice essential frequency range, the uncoupled, resulting normal force suffices to describe the transmission provided that the behaviour of the recipient is plate-like.