Measurement of thickness or plate velocity using ambient vibrations

Abstract

Abstract:Assuming the Green's function is linear with respect to the boundary conditions, it is demonstrated that flexural waves detected by a point receiver and a circular array of point receivers centered on the previous receiver are proportional regardless location of the source and geometry of the plate. Therefore determination of plate velocity or thickness is done from the measurement of ambient vibrations without using any emitter. Experimental results obtained with a plate of non regular geometry excited with a single transducer or a remote loudspeaker are shown to verify the theoretical approach.

Preliminary Study on the Acoustic Emission Wave Velocity on Filament Wound Glass Fiber Reinforced Polymer Pipes and its Correspondence with the Winding Angle

“…However, in the other hand, the absence of detailed information regarding how much effective these procedures are, caused uncertainty regarding the use of these methods in all kind of materials and structural members, i.e., filament wound composite pipes, without preliminary investigations. In this direction there are many studies, which where used the acoustic emission (AE) technique to investigate the failure mechanisms and the failure domain [7,8,9,10], but there is also a lack of information regarding the acoustic emission behavior for filament wound (FW) composite pipes made with alkali-resistant glass fiber.…”

Underwater depth reconstruction by local water wave measurements

“…This letter introduces an approach to water depth reconstruction which requires only the surface wave elevation information. It is based on basic properties of the solution to finite depth water wave equation; this so called circle method benefits from the Bessel series expansion of the solutions of the 2D linear wave equation (already used to study thickness and velocity of plates 7,8 ). The theoretical description of the problem is presented and the ability of the bottom shape characterization is demonstrated experimentally.…”