A Research On Acoustic Source Localization Technique Of Plate-like Structures Based On Lamb Waves

With the increasing number of metallic plate structures and the expansion of its applications,leak accident increases,threating the safety of human beings and properties.Although state-of-the-art technology can locate the continuous leak source effectively on simple plate structures,the localization of continuous leak source on complex structures lacks efficient solutions.This paper aims to study the leak source localization methods applied to the stiffened plate structures.Firstly,the transmission of Lambs waves on stiffened plate has been studied by both finite element simulations and experiments.Meantime,a series of two-dimensional finite element simulation models have been established along with the laser-Doppler-vibrometer-based experimental system.Data acquired by the simulations and experiments,accompanied with two-dimensional Fourier transform and transmission coefficient,are utilized to quantities the transmitted Lamb waves.Research results find out that stiffeners act like comb filters on Lamb waves with different frequencies and the number of passbands and passband width are influenced by the geometries of stiffeners(stiffener height,stiffener thickness and the heightthickness ratio of stiffeners).Based on the research result,a frequency-componentsbased map(FCBM)localization method has been proposed to locate the leak source on stiffened plate-like structures.Firstly,a grid system is constructed on the stiffened test plate.Then,several arbitrary distributed sensors are mounted on the test plate in order to collect frequency components data at each grid node via artificial continuous signal sources.And a frequency eigenvalue map is established by extracting frequency components data at each grid node.When unknown leak happens,the leak signal is processed and matched with the frequency eigenvalue map.And the location of the best matched grid node is regarded as the location of the unknown leak source.In the experiment,the size of the stiffened plate and the stiffener is 400×200×2.5 mm and 20×4 mm respectively.The distance between stiffeners is 100 mm.As a result,an average localization error of 21.7 mm is obtained by applying the FCBM method.This method has the merits of insensitivity to the frequency components of leak source and the ability to locate continuous leak source on complex structures.