scholarly journals Analysis of Guided Wave Propagation in a Multi-Layered Structure in View of Structural Health Monitoring

2019 ◽  
Vol 9 (21) ◽  
pp. 4600 ◽  
Author(s):  
Yevgeniya Lugovtsova ◽  
Jannis Bulling ◽  
Christian Boller ◽  
Jens Prager

Guided waves (GW) are of great interest for non-destructive testing (NDT) and structural health monitoring (SHM) of engineering structures such as for oil and gas pipelines, rails, aircraft components, adhesive bonds and possibly much more. Development of a technique based on GWs requires careful understanding obtained through modelling and analysis of wave propagation and mode-damage interaction due to the dispersion and multimodal character of GWs. The Scaled Boundary Finite Element Method (SBFEM) is a suitable numerical approach for this purpose allowing calculation of dispersion curves, mode shapes and GW propagation analysis. In this article, the SBFEM is used to analyse wave propagation in a plate consisting of an isotropic aluminium layer bonded as a hybrid to an anisotropic carbon fibre reinforced plastics layer. This hybrid composite corresponds to one of those considered in a Type III composite pressure vessel used for storing gases, e.g., hydrogen in automotive and aerospace applications. The results show that most of the wave energy can be concentrated in a certain layer depending on the mode used, and by that damage present in this layer can be detected. The results obtained help to understand the wave propagation in multi-layered structures and are important for further development of NDT and SHM for engineering structures consisting of multiple layers.

2016 ◽  
Vol 28 (9) ◽  
pp. 1211-1220 ◽  
Author(s):  
Pabitro Ray ◽  
Prabhu Rajagopal ◽  
Balaji Srinivasan ◽  
Krishnan Balasubramaniam

Harnessing of ultrasonic guided waves confined in local features such as bends and welds, known as feature-guided waves, has emerged as a promising technique for non-destructive testing and structural health monitoring of industrial and aerospace structures. This article introduces a fiber Bragg grating based technique which uses feature-guided waves to detect anomalies or defects in plate structures with transverse bends. We are able to obtain good consistency between simulation and experimental results, both in the case of defect-free bent plates and those with transverse defects. Such results establish fiber Bragg gratings as a viable alternative to conventional techniques for structural health monitoring of bent plates.


Author(s):  
Victor Giurgiutiu

Piezoelectric wafer active sensors (PWAS) are lightweight and inexpensive transducers that enable a large class of structural health monitoring (SHM) applications such as: (a) embedded guided wave ultrasonics, i.e., pitch-catch, pulse-echo, phased arrays; (b) high-frequency modal sensing, i.e., the electro-mechanical (E/M) impedance method; and (c) passive detection (acoustic emission and impact detection). The focus of this paper is on the challenges posed by using PWAS transducers in the composite structures as different from the metallic structures on which this methodology was initially developed. After a brief introduction, the paper reviews the PWAS-based SHM principles. It follows with a discussion of guided wave propagation in composites and PWAS tuning effects. Then, it discusses damage modes in composites. Finally, the paper presents some experimental results with damage detection in composite specimens. Hole damage and impact damage were detected using pitch-catch method with tuned guided waves being sent between a transmitter PWAS and a received PWAS. Root mean square deviation (RMSD) damage index (DI) were shown to correlate well with hole size and impact intensity. The paper ends with summary and conclusion; suggestions for further work are also presented.


Author(s):  
Byungseok Yoo ◽  
Darryll J. Pines ◽  
Ashish S. Purekar

Research interests in structural health monitoring have increased due to in-situ monitoring of structural components to detect damage. This can secure personal safety and reduce maintenance effort for mechanical systems. Conventional damage detection techniques known as nondestructive evaluation (NDE) have been conducted to detect and locate damaged area in structures. Ultrasonic testing, using ultrasonic transducers or electromagnetic acoustic transducers, is one of the most widespread NDE techniques, based on monitoring changes in acoustic impedance. Although the ultrasonic testing has advantages such as high sensitivity to discontinuities and evaluation accuracy, it requires testing surface accessibility, close location to the damaged area, and decent skill and training of technicians. In recent years, modal analysis techniques to capture changes of mode shapes and natural frequency of structures have been investigated. However, the technique is relatively insensitive to small amount of damage such as an initial crack which can rapidly grow in structures under cyclic loadings. In addition, structural health monitoring based on guided waves has become a preferred damage detection approach due to its quick examination of large area and simple inspection mechanisms. There are many techniques used to analyze sensor signals to bring out features related to damage. A phased array coupled with the guided wave approach has been introduced to effectively analyze complicated guided wave signals. Phased array theory as a directional filtering technique is usually used in antenna applications. By using phased array signal processing, virtually steering the array to find the largest response of source, the desired signal component can be enhanced while unwanted information is eliminated.


Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1445 ◽  
Author(s):  
Sergio Cantero-Chinchilla ◽  
Gerardo Aranguren ◽  
Muhammad Khalid Malik ◽  
Josu Etxaniz ◽  
Federico Martín de la Escalera

The development of reliable structural health monitoring techniques is enabling a healthy transition from preventive to condition-based maintenance, hence leading to safer and more efficient operation of different industries. Ultrasonic guided-wave based beamforming is one of the most promising techniques, which supports the monitoring of large thin-walled structures. However, beamforming has been typically applied to the post-processing stage (also known as virtual or receiver beamforming) because transmission or physical beamforming requires complex hardware configurations. This paper introduces an electronic structural health monitoring system that carries out transmission beamforming experiments by simultaneously emitting and receiving ultrasonic guided-waves using several transducers. An empirical characterization of the transmission beamforming technique for monitoring an aluminum plate is provided in this work. The high signal-to-noise ratio and accurate angular precision of the physical signal obtained in the experiments suggest that transmission beamforming can increase the reliability and robustnessof this monitoring technique for large structures and in real-world noisy environments.


Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7971
Author(s):  
Gaofeng Sha ◽  
Cliff J. Lissenden

Ultrasonic guided waves provide unique capabilities for the structural health monitoring of plate-like structures. They can detect and locate various types of material degradation through the interaction of shear-horizontal (SH) waves and Lamb waves with the material. Magnetostrictive transducers (MSTs) can be used to generate and receive both SH and Lamb waves and yet their characteristics have not been thoroughly studied, certainly not on par with piezoelectric transducers. A series of multiphysics simulations of the MST/plate system is conducted to investigate the characteristics of MSTs that affect guided wave generation and reception. The results are presented in the vein of showing the flexibility that MSTs provide for guided waves in a diverse range of applications. In addition to studying characteristics of the MST components (i.e., the magnetostrictive layer, meander electric coil, and biased magnetic field), single-sided and double-sided MSTs are compared for preferential wave mode generation. The wave mode control principle is based on the activation line for phase velocity dispersion curves, whose slope is the wavelength, which is dictated by the meander coil spacing. A double-sided MST with in-phase signals preferentially excites symmetric SH and Lamb modes, while a double-sided MST with out-of-phase signals preferentially excites antisymmetric SH and Lamb modes. All attempted single-mode actuations with double-sided MSTs were successful, with the SH3 mode actuated at 922 kHz in a 6-mm-thick plate being the highest frequency. Additionally, the results show that increasing the number of turns in the meander coil enhances the sensitivity of the MST as a receiver and substantially reduces the frequency bandwidth.


Author(s):  
Fei Yan ◽  
Joseph L. Rose ◽  
Roger L. Royer

Ultrasonic guided waves, due to theirs capability of interrogating a large structure from a single sensor position, has been proven as a promising tool for structural health monitoring (SHM). In this paper, we present two imaging approaches of utilizing guided wave leave-in-place sensors for early detection of defects in plate-like structures as well as for monitoring the defect growth. The first approach is based on a guided wave tomographic technique, in which the region surrounded by a sparse sensor array is monitored. The second one is a phased array approach, in which sensors are attached to a structure in a compact format to form an array. The region subjected to inspection and monitoring is the region outside the array. Both techniques have shown excellent capability of determining damage size, location, and severity.


2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Ming Li ◽  
Guang Meng ◽  
Hongguang Li ◽  
Jianxi Qiu ◽  
Fucai Li

This paper focuses on the establishment of the online structural health monitoring strategy for rotating shafts using ultrasonic guided waves. The dispersion of cylindrical shaft is investigated and a conclusion that the longitudinal ultrasonic wave propagating along the cylindrical shaft can hardly be interfered by the rotation is obtained. The experimental system and the numerical simulation model have been constructed, based on the fact that the experimental research and the numerical verification have been conducted intensively. The strategy can be concluded no matter the cracked rotor is at rest or rotating. Comparing with the same rotor without crack, the amplitudes of the guided wave packages descend along the transmission path and the symmetric path where crack exists; however, the amplitude of the wave packages will ascend along the other transmission paths.


Author(s):  
Olivier Mesnil ◽  
Arnaud Recoquillay ◽  
Tom Druet ◽  
Valentin Serey ◽  
Huu Tinh Hoang ◽  
...  

Abstract In Guided Wave Structural Health Monitoring (GW-SHM), a strong need for reliable and fast simulation tools has been expressed throughout the literature in order to optimize SHM systems or demonstrate performance. Even though guided wave simulations can be conducted with most finite elements software packages, computational and hardware costs are always prohibitive for large simulation campaigns. A novel SHM module has been recently added to the CIVA software and relies on unassembled high order finite elements to overcome these limitations. This paper focuses on the thorough validation of CIVA for SHM to identify the limits of the models. After introducing the key elements of the CIVA SHM solution, a first validation is presented on a stainless steel pipe representative of the oil and gas industry. Second, validation is conducted on a composite panel with and without stiffener representative of some structures in the aerospace industry. Results show an excellent match between the experimental and simulated datasets, but only if the input parameters are fully determined prior to the simulations.


2014 ◽  
Vol 553 ◽  
pp. 687-692 ◽  
Author(s):  
Ying Wang ◽  
Hong Hao

Among many structural health monitoring (SHM) methods, guided wave (GW) based method has been found as an effective and efficient way to detect incipient damages. In comparison with other widely used SHM methods, it can propagate in a relatively long range and be sensitive to small damages. Proper use of this technique requires good knowledge of the effects of damage on the wave characteristics. This needs accurate and computationally efficient modeling of guide wave propagation in structures. A number of different numerical computational techniques have been developed for the analysis of wave propagation in a structure. Among them, Spectral Element Method (SEM) has been proposed as an efficient simulation technique. This paper will focus on the application of GW method and SEM in structural health monitoring. The GW experiments on several typical structures will be introduced first. Then, the modeling techniques by using SEM are discussed.


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