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
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Composite Structures ◽  
Lamb Waves ◽  
Impact Damage ◽  
Composite Plates ◽  
Structural Features ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Structural Health

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.

Structural health monitoring for impact damaged composite: a new methodology based on a combination of techniques

2017 ◽  
Vol 17 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Ricardo de Medeiros ◽  
Dirk Vandepitte ◽  
Volnei Tita
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Impact Analysis ◽  
Residual Life ◽  
Impact Damage ◽  
Ceramic Matrix Composites ◽  
Composite Plates ◽  
Bending Test ◽  
Structural Health ◽  
Laminated Structures

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.

scholarly journals Impact Damage Detection in Composite Plates using a Self-diagnostic Electro-Mechanical Impedance-based Structural Health Monitoring System

2015 ◽  
Vol 06 (04) ◽  
pp. 1550013 ◽  
Author(s):  
Z. Sharif-Khodaei ◽  
M. Ghajari ◽  
M. H. Aliabadi
Keyword(s):  
Structural Health Monitoring ◽  
Damage Detection ◽  
Health Monitoring ◽  
Impact Damage ◽  
Composite Plates ◽  
Mechanical Impedance ◽  
Experimental Tests ◽  
Health Monitoring System ◽  
Structural Health ◽  
Faulty Sensors

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.

Structural Health Monitoring of Glass/Epoxy Composite Plates Using PZT and PMN-PT Transducers

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Valeria La Saponara ◽  
David A. Horsley ◽  
Wahyu Lestari
Keyword(s):  
Signal Processing ◽  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Wavelet Transforms ◽  
Composite Structures ◽  
Mode Conversion ◽  
High Stress ◽  
Composite Plates ◽  
Signal Processing Technique ◽  
Structural Health

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.

Structural Health Monitoring of Bonded Patch Repaired Composite

2016 ◽  
Vol 713 ◽  
pp. 135-138 ◽  
Author(s):  
Florian Lambinet ◽  
Zahra Sharif Khodaei ◽  
M.H. Ferri Aliabadi
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Composite Structures ◽  
Fatigue Testing ◽  
Impact Damage ◽  
Electromechanical Impedance ◽  
Structural Health ◽  
Repair Patch ◽  
Bonded Repair ◽  
First Case

Bonded repair of composite structures still remains a crucial concern for the airworthiness authorities because of the uncertainty about the repair quality. This works, investigates the applicability of Structural Health Monitoring (SHM) techniques for monitoring of bonded repair. Active sensing method has been applied to two case studies: a sensorised panel impacted to cause barely visible impact damage (BVID) and repaired afterwards, the tensile and fatigue testing of a composite strap repair. In the first case, the previous sensors have been used to detect an artificially introduced damage. In the second case the failure of the adhesive during the tensile testing is used as basis of the load levels in the tensile-tensile fatigue test. In both cases PZT transducers have been used to monitor the bonded patch. An electromechanical impedance (EMI) and Lamb wave analysis have been carried out to check the overall integrity of the repair patch between. In both cases the state of the repaired composite was monitored successfully and reported.

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