Comparison Study between RMS and Edge Detection Image Processing Algorithms for a Pulsed Laser UWPI (Ultrasonic Wave Propagation Imaging)-Based NDT Technique

Lee, Changgil; Zhang, Aoqi; Yu, Byoungjoon; Park, Seunghee

doi:10.3390/s17061224

Cited by 18 publications

(16 citation statements)

References 13 publications

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“…The vibration energy distribution is the basis for a simple but very efficient technique that utilizes the calculation of a root mean square (RMS). Recently, the RMS has been successfully used to detect defects in aluminium plates [14][15][16], delamination in a composite T-joint [17], disbonds in a stiffened panel [18], notches and corrosion areas in aluminium plates [19], disbond inserts in composite elements [20] and voids in adhesive joints [7]. The root mean square for a continuous signal s(t) is calculated with respect to the formula:…”

Section: Root Mean Squarementioning

confidence: 99%

Detection of debonding in adhesive joints using Lamb wave propagation

2019

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Adhesively bonded joints are widely used in many branches of industry. Mechanical degradation of this type of connections does not have significant symptoms that can be noticed during visual assessment, so non-destructive testing becomes a very important issue. The paper deals with experimental investigations of adhesively bonded steel plates with different defects. Five samples (an intact one and four with damages in the form of partial debonding) were prepared. The inspection was conducted with the use of guided wave propagation method. Lamb waves were excited at one point of the sample, whereas the out-of-plane velocity signals were recorded in a number of points spread over the area of overlap. The processing of signals consisted of calculations of weighted root mean square (WRMS). The results of the analysis showed that the WRMS maps allow for identification and determination of size and shape of debonding areas.

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Section: Root Mean Squarementioning

confidence: 99%

Detection of debonding in adhesive joints using Lamb wave propagation

2019

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“…This processing technique depends on the calculation of the weighted root mean square for each registered time signal and the creation of a damage map. The WRMS for a time signal s(t) can be defined as follows [25,26,30,33,36]…”

Section: Weighted Root Mean Square Damage Imagingmentioning

confidence: 99%

“…This method was improved to be more applicable for damage detection by defining the weighted root mean square (WRMS) method [30]. Recently, the RMS has been successfully used in various damage detection applications [25,26,[31][32][33][34][35][36].Żak et al [30] investigated aluminum and composite plates as well as composite elements of a helicopter, all with the damage being simulated by an additional mass. They concluded that better resolution in WRMS maps corresponded to higher values of the weighting factor (linear or square).…”

Section: Introductionmentioning

confidence: 99%

“…In the conducted works, only higher frequencies (250 kHz and 300 kHz) were able to detect damage. Lee et al [36] applied the WRMS to localize the notches and corrosion areas in aluminum plates and chose 2 as the weighting parameter. Kudela et al [25] studied the detection of delamination in a composite plate using WRMS with the weighting factor set as 2.7.…”

Section: Introductionmentioning

confidence: 99%

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Damage Imaging in Lamb Wave-Based Inspection of Adhesive Joints

2018

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Adhesive bonding has become increasingly important in many industries. Non-destructive inspection of adhesive joints is essential for the condition assessment and maintenance of a structure containing such joints. The aim of this paper was the experimental investigation of the damage identification of a single lap adhesive joint of metal plate-like structures. Nine joints with different defects in the form of partial debonding were considered. The inspection was based on ultrasonic guided wave propagation. The Lamb waves were excited at one point of the analyzed specimen by means of a piezoelectric actuator, while the guided wave field was measured with the use of a laser vibrometer. For damage imaging, the recorded out-of-plane vibrations were processed by means of the weighted root mean square (WRMS). The influence of different WRMS parameters (i.e., the time window and weighting factor), as well as excitation frequencies, were analyzed using statistical analysis. The results showed that two-dimensional representations of WRMS values allowed for the identification of the presence of actual defects in the adhesive film and determined their geometry.

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“…With the rapid development of laser machining technology, laser machining systems with galvano scanners have become indispensable in laser processing industrial techniques such as welding, cutting, sculpting, drilling, marking, mode filling, and surface treatment. (1)(2)(3)(4)(5)(6) The laser machining systems with galvano scanners can be used to effectively replace the traditional machinery machining approach according to the following advantages: (1) noncontact treatment, (2) absence of pollution, (3) high movement speed, (4) prevention of tool wear, (5) high precision, and (6) high efficiency. In addition, the laser galvanometer scanning systems are widely utilized in material processing because they can control the laser spot more accurately and rapidly than other scanning systems for producing a small and uniform laser spot size in an objective flat field.…”

Section: Introductionmentioning

confidence: 99%

Vibration Measurement and Suppression for Laser Galvanometers Using a Micro-electromechanical System-based Accelerometer

Chou¹,

Hsu²,

Yang³

et al. 2018

Sensors and Materials

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In this study, we develop a vibration measurement, analysis, and suppression system for laser galvanometers. A galvanometer control system integrates a notebook computer, an intelligent motion control platform (IMP-2), a servo driver circuit, and a galvanometer driver module for driving laser galvanometers. The proposed vibration measurement, analysis, and suppression system composed of a micro-electromechanical system (MEMS) piezoelectric accelerometer, the fast Fourier transformation (FFT) algorithm operated on a notebook computer, and an analog comb filter circuit is utilized to measure, analyze, and suppress vibrations generated from the mirror-installed galvanometer motors during rotation motions, respectively. First, we use the MEMS-based accelerometer to measure and record the vibration signals from the mirror-installed galvanometer motors during rotation motions. Second, we carry out the frequency spectrum analysis of vibration acceleration signals using the FFT algorithm. Subsequently, we design an efficient analog comb filter on the basis of the observed harmonic or resonance frequencies for suppressing the galvanometer vibrations. Finally, on the basis of the experimental results, we successfully validate that the proposed inertial-sensing-based vibration measurement, analysis, and suppression system can measure and analyze the galvanometer vibrations, and suppress them effectively to improve the accuracy and stability of the laser galvanometer scanning systems.

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Comparison Study between RMS and Edge Detection Image Processing Algorithms for a Pulsed Laser UWPI (Ultrasonic Wave Propagation Imaging)-Based NDT Technique

Cited by 18 publications

References 13 publications

Detection of debonding in adhesive joints using Lamb wave propagation

Detection of debonding in adhesive joints using Lamb wave propagation

Damage Imaging in Lamb Wave-Based Inspection of Adhesive Joints

Vibration Measurement and Suppression for Laser Galvanometers Using a Micro-electromechanical System-based Accelerometer

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