Damage Detection in a Composite T-Joint using Guided Lamb Waves

To perform active structural health monitoring, guided Lamb waves for damage detection have recently gained extensive attention. Many algorithms are used for damage detection with guided waves and among them, the delay-and-sum method is the most commonly used algorithm because of its robustness and simplicity. However, delay-and-sum images tend to have poor accuracy with a large spot size and a high noise floor, especially in the presence of multiple damages. To overcome these problems, another method that is based on sparse reconstruction can be used. Although the images produced by the sparse reconstruction method are superior to the conventional delay-and-sum method, it has the challenges of the time and cost of computations in comparison with the delay-and-sum method. Also, in some cases in multi-damage detection, the sparse reconstruction method totally fails. In this article, using prior support information of the structure achieved by the delay-and-sum method, a hybrid method based on sparse reconstruction method is proposed to improve the computational performance and robustness of sparse reconstruction method in the case of multi-damage presence. The effectiveness of the proposed method in detecting damages is demonstrated experimentally and numerically on a simple aluminum plate. The technique is also shown to accurately identify and localize multi-site damages as well as single damage with low sampled signals.

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Lamb Waves Signal Analysis in Structural Health Monitoring Systems

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.368-373.2402 ◽

2011 ◽

Vol 368-373 ◽

pp. 2402-2405

Author(s):

Nai Zhi Zhao ◽

Chang Tie Huang ◽

Xin Chen

Keyword(s):

Structural Health Monitoring ◽

Damage Detection ◽

Health Monitoring ◽

Structural Changes ◽

Lamb Waves ◽

Detection Algorithm ◽

Operational Conditions ◽

Structural Health ◽

Detection Algorithms ◽

Baseline Subtraction

Many of the wave propagation based structural health monitoring techniques rely on some knowledge of the structure in a healthy state in order to identify damage. Baseline measurements are recorded when a structure is pristine and are stored for comparison to future data. A concern with the use of baseline subtraction methods is the ability to discern structural changes from the effects of varying environmental and operational conditions when analyzing the vibration response of a system. The use of a standard baseline subtraction technique may falsely indicate damage when environmental or operational variations are present between baseline measurements and new measurements. A procedure was outlined for the method, including excitation and recording of Lamb waves, and the use of damage detection algorithms. In this paper, several tests are performed and the results are used to help develop the damage detection algorithms previously described, and to evaluate the performance of the instantaneous baseline SHM technique. Analytical testing is first performed by feeding known input signals into each damage detection algorithm and analyzing the output data. The results of the analytical testing are used to help develop the damage detection algorithms.

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An On-Line Multiway Approach to In-Situ NDI Looking at the PZL-130TCII

Fatigue of Aircraft Structures ◽

10.2478/fas-2013-0001 ◽

2014 ◽

Vol 2013 (5) ◽

pp. 5-11 ◽

Cited By ~ 1

Author(s):

Krzysztof Dragan ◽

Michał Dziendzikowski ◽

Artur Kurnyta ◽

Adam Latoszek ◽

Andrzej Leski ◽

...

Keyword(s):

Damage Detection ◽

Hot Spots ◽

Lamb Waves ◽

Holistic Approach ◽

Growth Monitoring ◽

Damage Growth ◽

On Line ◽

Detection Capabilities ◽

Main Component

Abstract Providing a reliable and universal Structural Health Monitoring (SHM) system allowing for remote aircraft inspections and a reduction of maintenance costs is a major challenge confronting the aerospace industry today. SHM based on guided Lamb waves is one of the approaches capable of addressing the issue while satisfying all the associated requirements. This paper presents a holistic approach to the continuous real time damage growth monitoring and early damage detection in aircraft structure. The main component of the system is a piezoelectric transducers (PZT) network. It is complemented by other SHM methods: Comparative Vacuum Monitoring (CVMTM) and Resistance Gauges at selected aircraft hot spots. The paper offers the description of damage detection capabilities including the analysis of data collected from the PZL-130 Orlik aircraft full-scale fatigue test.

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Damage Detection Using Lamb Waves (Review)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1028.161 ◽

2014 ◽

Vol 1028 ◽

pp. 161-166 ◽

Cited By ~ 1

Author(s):

Zai Lin Yang ◽

Hamada M. Elgamal ◽

Yao Wang

Keyword(s):

Damage Detection ◽

Health Monitoring ◽

Guided Waves ◽

Damage Identification ◽

Lamb Waves ◽

Long Distance ◽

The Past ◽

Thin Walled Structures ◽

Thin Walled ◽

Analytical Complexity

Several techniques have been researched for detecting damage in plates. Each of these techniques offers their own unique advantages in detecting certain types of damage with various levels of analytical complexity. Lamb waves are guided waves that exist in thin walled structures. Because this type of wave can travel long distance with little attenuation, they have been studied intensively for structural health monitoring, especially in the past few decades. This paper presents an overview of using the Lamb waves in damage detection including the theory of lamb waves and the lamb-wave-based damage identification.

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Lamb wave generation using nanosecond laser ablation to detect damage

Journal of Vibration and Control ◽

10.1177/1077546316687904 ◽

2017 ◽

Vol 24 (24) ◽

pp. 5842-5853 ◽

Cited By ~ 13

Author(s):

Naoki Hosoya ◽

Ryosuke Umino ◽

Atsushi Kanda ◽

Itsuro Kajiwara ◽

Atsushi Yoshinaga

Keyword(s):

Laser Ablation ◽

Damage Detection ◽

Lamb Wave ◽

Lamb Waves ◽

Wave Generation ◽

Nanosecond Laser ◽

Large Area ◽

Contact Damage ◽

Contact Type ◽

Aluminum Alloy 2024

This paper proposes a non-contact damage detection method based on Lamb waves generated by laser ablation (LA). Previously, Lamb waves generated by contact-type sensors such as acoustic emission or piezoelectric zirconate titanate devices have been studied to detect damage. Lamb wave generation systems with embedded contact-type excitation devices to objective structures to be inspected may quickly realize large-area damage detection on a huge object such as an aircraft. However, replacing contact-type devices with non-contact devices in Lamb wave generation systems, the systems will have sufficient potential to excite under the specific conditions such as submerged target structures in liquid and high-temperature substances. The LA-generated Lamb waves that have amplitudes several hundred times larger than those generated by conventional laser-thermoelastically generated Lamb waves are of advantage from the viewpoint of the signal-to-noise ratio in the measurements. When the laser fluence reaches 1012–1014 W/m2, which is greater than that for laser-thermoelastic regime, a LA regime is induced. The amplitudes of the LA-generated Lamb waves might be higher than those of the laser-thermoelastically generated Lamb waves; this is within the scope of the assumption. Since the LA process entails a number of nonlinear processes such as melting, vaporization, and sublimation, it is important to confirm that LA could generate a Lamb wave and its mode. In this paper, Lamb waves that contain broadband frequency elements of more than several hundred kHz are generated by non-contact impulse excitation using LA, which is common in vibration tests in the high-frequency range, laser peening, propulsion of micro-aircraft, bolt loosening diagnosis, etc. The present method is evaluated by comparing the measured and calculated propagation phase and group velocities of the Lamb waves. Furthermore, the feasibility of our approach is demonstrated by non-contact damage detection against an aluminum alloy 2024 plate with a crack.

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