Experiments with Free Vibration of Light Roofs Backed by Cavities
Publication: Journal of Engineering Mechanics
Volume 116, Issue 8
Abstract
This paper complements the theoretical study of the same subject. The aim is to verify the theory formulated in the companion paper. Free vibration of large‐span, self‐supported, lightweight roofs backed by cavities with wall openings is experimentally investigated in the laboratory using two model roofs: a circular membrane roof and a flexible, circular plate behaving in a flexural way. Similarity requirements of the roof‐air system are reviewed. The influence of wall openings on the frequencies and total damping of the structure is investigated. Comparison of the experimental results with those of the theoretical analysis formulated by the writers is made. Excellent agreement between the theory and experiments is obtained. The notions of a leaking kettledrum and a Helmholtz oscillator with a flexible wall are confirmed. The air movement through the wall openings as well as the acoustical damping associated with the motion of both the roof and the air mass at the openings have significant effects on roof natural frequencies and modal damping. The volume of the enclosure under the roof has also a marked effect.
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Published In
Journal of Engineering Mechanics
Volume 116 • Issue 8 • August 1990
Pages: 1750 - 1763
Copyright
Copyright © 1990 ASCE.
History
Published online: Aug 1, 1990
Published in print: Aug 1990
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