Propagation Characteristics of Acoustic Emission Signals in Stiffened Cylindrical Shells Based on the Multipath Propagation Model

Cong Han,Guoan Yang,Tong Liu,Zhenhuan Wu

doi:10.3390/app112411722

Cong Han, Guoan Yang + Show 2 more

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https://doi.org/10.3390/app112411722

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Journal: Applied sciences	Publication Date: Dec 10, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Beijing University of Chemical Technology

Abstract

A stiffener attached to a cylindrical shell strongly interferes with the propagation of the acoustic emission (AE) signal from the fault source and reduces the fault detection accuracy. The interaction of AE signals with the stiffener on the cylindrical shell is thoroughly investigated in this paper. Based on the proposed model of the AE signal propagating inside the cylindrical shell with a stiffener, the installation constraints for the sensor are derived, resulting in the separation of the direct signal, the stiffener scattering signal, and other signals in the time domain. On this basis, combinations of the excitation frequency and the stiffener height are simulated, and the reflection and transmission of the AE signal in each case are quantitatively characterized by the scattering coefficients. The results indicate that there is a “T-shaped” transformation of the signal at the stiffener, which evolves into a variety of other modes. Moreover, the reflection and transmission coefficients of the incident AE signal are displayed as a function of the excitation frequency and the height of the stiffener. In addition, the accuracy of the scattering coefficients obtained from the numerical simulations is verified by experiments, and a good consistency between simulation results and experiment results is presented. This work illustrates the propagation characteristics of AE signals in a cylindrical shell with a stiffener, which can be used as guidance for optimizing the spatial arrangement of sensors in AE monitoring.

Highlights

Acoustic emission (AE) technology is widely applied in structural health monitoring (SHM) and nondestructive evaluation (NDE) due to its remarkable advantages such as dynamic, sensitivity, integrity, and timeliness [1,2,3]
This study proposes the multipath propagation model about the AE signal propagate in a stiffened cylindrical shell and derives the constraint conditions for monitoring positions to separate the direct signal, stiffener scattering signals, and other signals in the time domain
The reflection waveform and the transmission waveform are received by following a similar procedure on the stiffened cylindrical shell

Summary

Introduction

Acoustic emission (AE) technology is widely applied in structural health monitoring (SHM) and nondestructive evaluation (NDE) due to its remarkable advantages such as dynamic, sensitivity, integrity, and timeliness [1,2,3]. Chen et al [5] measured the AE characteristics of collapsing holes and the movements of dislocations in Mg-Ho alloys during structural collapse, and the analysis showed that porous collapse is fully consistent with Bath’s law, while dislocation movements are not. Chen et al [6] used the profile analysis of AE signals and characteristic parameters to distinguish dislocation movements and dynamic entanglements in fcc 316L stainless steel. Salje [8] clarified the local structure of jammed twin boundary patterns using computer simulation and found that the friction in ferroelastomer and martensite is associated with movement of the boundary and other microstructures. Salje et al [9]

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