Structural Health Monitoring of Composite Structures Using Guided Lamb Waves

2006 ◽  
Vol 321-323 ◽  
pp. 759-764 ◽  
Author(s):  
Krishnan Balasubramaniam ◽  
B.V. Soma Sekhar ◽  
J. Vishnu Vardan ◽  
C.V. Krishnamurthy

Structural Health Monitoring (SHM) of aircrafts is of great relevance in the present age aircraft industry. The present study demonstrates three techniques that have the potential for the SHM of multi-layered composite structures. The first technique is based on multi-transmitter-multireceiver (MTMR) technique with tomographic methods used for data reconstruction. In the MTMR, the possibility of SHM using algebraic reconstruction techniques (ART) for tomographic imaging with Lamb wave data measured in realistic materials is examined. Defects (through holes and low velocity impact delaminations) were synthetic and have been chosen to simulate impact damage in composite plates. The second technique is a single-transmitter-multi-receiver (STMR) technique that is more compact and uses reconstruction techniques that are analogous to synthetic aperture techniques. The reconstruction algorithm uses summation of the phase shifted signals to image the location of defects, portions of the plate edges, and any reflectors from inherent structural features of the component. The third technique involves a linear array of sensors across a stiffener for the detection of disbanded regions.

2017 ◽  
Vol 17 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Ricardo de Medeiros ◽  
Dirk Vandepitte ◽  
Volnei Tita

Advanced aerospace materials, including fibre-reinforced polymer and ceramic matrix composites, are increasingly being used in critical and demanding applications, challenging not only the current damage prediction, detection and quantification methodologies, but also the residual life of the structure. The main objective of this work consists of developing a new methodology based on different techniques to be applied on structural health monitoring system for impacted composite aeronautic structures. For this, it is necessary to identify, and to localise damage, as well as to calculate the severity of the damage and to predict the residual strength of the composite structure. To achieve these goals, the research methodology should consider three methods: (1) vibration-based method, (2) shearography speckle and (3) flexural after impact. Composite plates, made of epoxy resin reinforced by carbon fibre, are evaluated. First, vibration-based method provides frequency response functions to be analysed by a new metric, which is compared in terms of their capability for damage identification and global location. Afterwards, the extension of impact damage is determined using shearography speckle. This technique has demonstrated great potential for damage detection in composite-laminated structures. A flexure after impact test is used to evaluate its limitations and potentialities as a damage-tolerance technique. The residual flexural strength of damaged specimens is evaluated by quasi-static four-point bending test. A new criterion based on a relationship between damage metric from vibration-based method and flexure after impact analysis is presented and discussed. Finally, it discussed the advantages and limitations of this combination of techniques into the context of structural health monitoring systems.


2015 ◽  
Vol 06 (04) ◽  
pp. 1550013 ◽  
Author(s):  
Z. Sharif-Khodaei ◽  
M. Ghajari ◽  
M. H. Aliabadi

In this work, application of the electro-mechanical impedance (EMI) method in structural health monitoring as a damage detection technique has been investigated. A damage metric based on the real and imaginary parts of the impedance measures is introduced. Numerical and experimental tests are carried out to investigate the applicability of the method for various types of damage, such as debonding between the transducers and the plate, faulty sensors and impact damage in composite plates. The effect of several parameters, such as environmental effects, frequency sweep, severity of damage, location of damage, etc., on the damage metric has been reported.


Author(s):  
Valeria La Saponara ◽  
David A. Horsley ◽  
Wahyu Lestari

The structural health monitoring of composite structures presents many challenges, ranging from sensors’ reliability and sensitivity to signal processing and a robust assessment of life to failure. In this research project, sensors constructed with both PZT-4 ceramic and single-crystal PMN-PT, i.e., Pb(Mg1/3Nb2/3)O3−PbTiO3, were investigated for structural health monitoring of composite plates. Fiberglass/epoxy specimens were manufactured with a delamination starter located in the middle of the plate, and were subjected to axial tensile fatigue at a high stress ratio. A surface-mounted PMN-PT pair and a surface-mounted PZT-4 pair were positioned on each side of the delamination starter and excited in turns at set intervals during fatigue loading. This project had two goals: (1) assess the performance of the two piezoelectric materials and (2) develop a signal processing technique based on wavelet transforms capable of detecting damage features that are independent of the transducers (being damaged concurrently to the host composite specimens) and thus can estimate life to failure of the composite specimens. Results indicate that the PMN-PT transducers may be more resilient to fatigue damage of the host structure and possibly generate less dispersive Lamb waves. However, these aspects are compounded with higher costs and manufacturing difficulties. Moreover, the proposed signal processing method shows promise in estimating impending failure in composites: It could, in principle, capture and quantify the complex wave propagation problem of dispersion, scattering, and mode conversion across a delamination front, and it will be further investigated.


Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 153
Author(s):  
Sahar Hassani ◽  
Mohsen Mousavi ◽  
Amir H. Gandomi

This study presents a comprehensive review of the history of research and development of different damage-detection methods in the realm of composite structures. Different fields of engineering, such as mechanical, architectural, civil, and aerospace engineering, benefit excellent mechanical properties of composite materials. Due to their heterogeneous nature, composite materials can suffer from several complex nonlinear damage modes, including impact damage, delamination, matrix crack, fiber breakage, and voids. Therefore, early damage detection of composite structures can help avoid catastrophic events and tragic consequences, such as airplane crashes, further demanding the development of robust structural health monitoring (SHM) algorithms. This study first reviews different non-destructive damage testing techniques, then investigates vibration-based damage-detection methods along with their respective pros and cons, and concludes with a thorough discussion of a nonlinear hybrid method termed the Vibro-Acoustic Modulation technique. Advanced signal processing, machine learning, and deep learning have been widely employed for solving damage-detection problems of composite structures. Therefore, all of these methods have been fully studied. Considering the wide use of a new generation of smart composites in different applications, a section is dedicated to these materials. At the end of this paper, some final remarks and suggestions for future work are presented.


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