Damage identification in aluminum plates based on iterative partition algorithm using waveform centroid

SHM is defined as “an emerging technology that can be defined as continuous, autonomous, real time, in-service monitoring of the physical condition of a structure by means of embedded or attached sensors with minimum manual intervention” .SHM provides the ability of a system to detect adverse changes within a system’s structure to enhance reliability and reduce maintenance costs. There are different Non-Destructive techniques like acoustic emission, ultrasonic, acousto-ultrasonic, guided ultrasonic waves or Lamb waves which are nowadays investigated for the development of an efficient and user-friendly damage identification system. This paper deals with the latter which is based on Lamb wave propagation. It has been developed especially for distinguishing different kinds of damages. The Lamb wave-based active SHM method uses piezoelectric (PZT) sensors to transmit and receive Lamb waves in a thin Aluminum plate. The Lamb wave modes (AO &SO) travel into the structure and are reflected by the structural boundaries, discontinuities, and damage. By studying their propagation and reflection, the presence of defect in the structure is determined. Laboratory level experiments have been carried out on thin Aluminum plates with angular, horizontal and vertical defect. The obtained waveform is filtered to avoid unwanted noise & disturbances using Savitzky-Golay filtering. The filtered waveforms are compared to differentiate the defects. Short Time Fourier Transform has been carried out on the acquired waveform. This study provides significant insight into the problem of identifying localized damages in the structure using PZT and dispersion of signal after they interact with different types of damage. Those small defects like the horizontal one that may be nearly missed in time domain analysis can also be clearly identified in the STFT analysis. Moreover the occurrence of So mode is also clearly seen. Thus, Lamb waves generated by PZT sensors and time-frequency analysis techniques could be used effectively for damage detection in aluminum plate. This study has given a complete idea of the working and the basic requirements of SHM system.

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Probabilistic Damage Identification Based on Correlation Analysis Using Guided Wave Signals in Aluminum Plates

Structural Health Monitoring ◽

10.1177/1475921709352145 ◽

2009 ◽

Vol 9 (2) ◽

pp. 133-144 ◽

Cited By ~ 78

Author(s):

Dong Wang ◽

Lin Ye ◽

Zhongqing Su ◽

Ye Lu ◽

Fucai Li ◽

...

Keyword(s):

Correlation Analysis ◽

Damage Identification ◽

Guided Wave ◽

Aluminum Plates

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A Novel Complementary Method for the Point-Scan Nondestructive Tests Based on Lamb Waves

International Journal of Aerospace Engineering ◽

10.1155/2014/351840 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Rahim Gorgin ◽

Zhanjun Wu ◽

Yuebin Zheng

Keyword(s):

Lamb Wave ◽

Test Piece ◽

Damage Identification ◽

Lamb Waves ◽

Complementary Method ◽

Nondestructive Tests ◽

Damage Probability ◽

Scan Test ◽

Aluminum Plates ◽

Probability Index

This study presents a novel area-scan damage identification method based on Lamb waves which can be used as a complementary method for point-scan nondestructive techniques. The proposed technique is able to identify the most probable locations of damages prior to point-scan test which lead to decreasing the time and cost of inspection. The test-piece surface was partitioned with some smaller areas and the damage probability presence of each area was evaluated.A0mode of Lamb wave was generated and collected using a mobile handmade transducer set at each area. Subsequently, a damage presence probability index (DPPI) based on the energy of captured responses was defined for each area. The area with the highest DPPI value highlights the most probable locations of damages in test-piece. Point-scan nondestructive methods can then be used once these areas are found to identify the damage in detail. The approach was validated by predicting the most probable locations of representative damages including through-thickness hole and crack in aluminum plates. The obtained experimental results demonstrated the high potential of developed method in defining the most probable locations of damages in structures.

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Use of Relative Baseline Features of Guided Waves for In situ Structural Health Monitoring

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x10395643 ◽

2011 ◽

Vol 22 (2) ◽

pp. 175-189 ◽

Cited By ~ 13

Author(s):

Jeong-Seok Lee ◽

Gyuhae Park ◽

Chun-Gon Kim ◽

Charles R. Farrar

Keyword(s):

Environmental Conditions ◽

Structural Damage ◽

Guided Waves ◽

Damage Identification ◽

Lamb Waves ◽

Processing Technique ◽

Data Sets ◽

Signal Processing Technique ◽

Power Spectral ◽

Aluminum Plates

This article presents a new signal-processing technique, which utilizes ‘‘relative baselines’’ instead of ‘‘pre-stored baselines,’’ for Lamb wave based SHM. Several successful SHM methods utilizing wave propagations usually involve recording baseline measurements and comparing them to a newly measured response for structural damage identification. However, maintaining an accurate database of baselines remains challenging because of the effects of varying environmental conditions. Therefore, in this study, the relative baseline concept is proposed, in which measured Lamb waves are correlated between different sensor-actuator sets, as opposed to being correlated to pre-stored baseline data. This study focuses on determining the feature best used for this relative baseline concept, and cross-correlation and power spectral density analysis techniques are performed on data sets recorded from composite and aluminum plates. Experiments are performed with these plates under the presence of temperature variations in order to demonstrate the capability of the relative baseline concept. Our experimental results clearly indicate that the proposed technique reduces the complications associated with using pre-stored baselines for SHM under varying environmental conditions, and provides a quantitative means of identifying structural damage.

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Noncontact Air-Coupled Guided Wave Ultrasonics for Detection of Thinning Defects in Aluminum Plates

Research in Nondestructive Evaluation ◽

10.1080/09349840108968178 ◽

2001 ◽

Vol 13 (1) ◽

pp. 61-77 ◽

Cited By ~ 2

Author(s):

D. Tuzzeo ◽

F. Lanza di Scalea

Keyword(s):

Guided Wave ◽

Aluminum Plates

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Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

Mechanics & Industry ◽

10.1051/meca/2020061 ◽

2020 ◽

Vol 21 (5) ◽

pp. 505

Author(s):

Yousef Ghaderi Dehkordi ◽

Ali Pourkamali Anaraki ◽

Amir Reza Shahani

Keyword(s):

Residual Stress ◽

Cyclic Loading ◽

Stress Relaxation ◽

Stress Amplitude ◽

Cyclic Plasticity ◽

Mean Stress ◽

Effective Parameters ◽

Perfect Plasticity ◽

Residual Stress Relaxation ◽

Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

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