| The offshore platform serves in complex bad Marine environment with highmaintenance cost is higher in the long time, so the regular inspection and onlinereal-time monitoring to ensure the normal production and safety operation are needed.As a new type of dynamic nondestructive testing method, Acoustic emissiontechnology can monitor the material produces the defects dynamically and predict thedamage position. Acoustic emission source release elastic wave under the externalload with lots of information of structure or material damage, by receiving andanalyzing the acoustic emission signal to identify and locate the structure or materialof damage, the purpose of the real-time monitoring of the structure to prevent aserious accident can be achieved.Based on the study of the theory, firstly this paper explains the mechanism of thematerial dislocation motion and crack initiation and the expansion of acousticemission source, meanwhile introduces the principle of acoustic emission monitoringtechnology, acoustic emission wave propagation model, speed in all kinds of mediumand the attenuation characteristics.Contrastively introduce conventional AE source location methods and principles,put forward a location algorithm based on time arrive (TDOA) which is applied to theAE source location, apply the TDOA estimation theory and weighted leastsquares(WLS) to achieve location, improve the precision and lower the cost.Set up acoustic emission signal simulation model in one-dimensional structurematerials, stimulate the law of stress wave propagation in the structure, make researchon the transmission characteristics of acoustic emission signal in one-dimensionalstructure material. Verify the rule of the stress propagation along the axis of thedirection stem over time domain, by limiting the expansion of the wave speed toinfluence the stable limit, use whole estimation method to determine the limit stability,obtain accurate state of the structure. |
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