Lamb Wave Local Wavenumber Approach for Characterizing Flat Bottom Defects in an Isotropic Thin Plate

Fan, Guopeng; Zhang, Haiyan; Zhang, Hui; Zhu, Wen-Fa; Chai, Xiaodong

doi:10.3390/app8091600

Cited by 10 publications

(8 citation statements)

References 39 publications

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“…A five-cycle sinusoidal tone burst signal from a Hanning window was used as the excitation signal in this paper, and the other experimental parameters are listed in Table 1. The phased array transducer was placed above the aluminum plate as shown in Figure 2, which was suitable to excite the S0 mode Lamb waves with a frequency-thickness product of 1 MHz·mm [26,27]. In our test, the group velocity of the S0 mode was about 5300 m/s, and the wavelength of the S0 mode was 5.3 mm.…”

Section: Methodsmentioning

confidence: 96%

Sparse-TFM Imaging of Lamb Waves for the Near-Distance Defects in Plate-Like Structures

Zhang

Lin

Fan

et al. 2019

Metals

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The ultrasonic phased array total focusing method (TFM) has the advantages of high imaging resolution and high sensitivity to small defects. However, it has a long imaging time and cannot realize near-distance defect imaging, which limits its application for industrial detection. A sparse-TFM algorithm is adopted in this work to solve the problem regarding rapid imaging of near- distance defects in thin plates. Green’s function is reconstructed through the cross-correlation of the diffuse full matrix captured by the ultrasonic phased array. The reconstructed full matrix recovers near-distance scattering information submerged by noise. A sparse array is applied to TFM for rapid imaging. In order to improve the imaging resolution, the location of active array elements in the sparse array can be optimized using the genetic algorithm (GA). Experiments are conducted on three aluminium plates with near-distance defects. The experimental results confirm that the sparse-TFM algorithm of Lamb waves can be used for near-distance defects imaging, which increases the computational efficiency by keeping the imaging accuracy. This paper provides a theoretical guidance for Lamb wave non-destructive testing of the near-distance defects in plate-like structures.

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Section: Methodsmentioning

confidence: 96%

Sparse-TFM Imaging of Lamb Waves for the Near-Distance Defects in Plate-Like Structures

Zhang

Lin

Fan

et al. 2019

Metals

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“…The results showed that the ANN was an effective tool for damage location in a plate structure. The local wavenumber method of Lamb waves was used by Fan et al [43] to characterize the flat bottom defects in isotropic thin plates. The simulation and experimental results showed that the average wavenumber Appl.…”

Section: Defects Identification Methodsmentioning

confidence: 99%

“…Sci. 2019, 9, wavenumber method of Lamb waves was used by Fan et al [43] to characterize the flat bottom defects in isotropic thin plates. The simulation and experimental results showed that the average wavenumber could be used to not only identify the shape, position, and size of the damage but also quantify the depth of the damage.…”

Section: Testing Object and Artificial Defectmentioning

confidence: 99%

The Rapid Detection Technology of Lamb Wave for Microcracks in Thin-Walled Tubes

Wang

Yang

2019

Applied Sciences

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Thin-walled tubes are a kind of pressure vessel formed by a stamping and drawing process, which must withstand a great deal of sudden pressure during use. When microcrack defects of a certain depth are present on its inner and outer surfaces, severe safety accidents may occur, such as cracking and crushing. Therefore, it is necessary to carry out nondestructive testing of thin-walled tubes in the production process to eliminate the potential safety hazards. To realize the rapid detection of microcracks in thin-walled tubes, this study could be summarized as follows: (i) Because the diameters of the thin-walled tubes were much larger than their thicknesses, Lamb wave characteristics of plates with equal thicknesses were used to approximate the dispersion characteristics of thin-walled tubes. (ii) To study the dispersion characteristics of Lamb waves in thin plates, the detection method of the A 0 mode was determined using the particle displacement-amplitude curve. (iii) Using a multi-channel parallel detection method, rapid detection equipment for Lamb wave microcracks in thin-walled tubes was developed. (iv) The filtering peak values for defect signal detection with different depths showed that the defect detection peak values could reflect the defect depth information. (v) According to the minimum defect standard of a 0.045-mm depth, 100,000 thin-walled tubes were tested. The results showed that the missed detection rate was 0%, the reject rate was 0.3%, and the detection speed was 5.8 s/piece, which fully meets the actual detection requirements of production lines. Therefore, this study not only solved the practical issues for the rapid detection of microcracks in thin-walled tubes but also provided a reference for the application of ultrasonic technology for the detection of other components. Appl. Sci. 2019, 9, 3576 2 of 15 quantitatively, which can easily lead to misjudgment [10]. Magnetic particle testing is more suitable for surface defect detection, and it is difficult to quantitatively detect the depth of a flaw [10]. The X-ray method is mainly used to detect the volume of the defect inside the object. For an area defect, there will be an overlap of the front and back, and the angle between the ray beam and the orientation of the crack cannot exceed 10 • ; otherwise, it cannot be detected [10]. Penetration detection is limited to the defects of the surface opening. The penetrating liquid pollutes the parts and the environment and is not suitable for on-line detection [10]. Ultrasonic testing is sensitive to the area of the defect inside the object and can locate the relative size and location of the defect. The detection depth is much greater than other detection methods, and thus, it has been widely used [10]. For thin-walled tubes, ultrasonic Lamb waves are usually used for testing [11].The ultrasonic detection principle of thin-walled tubes is the same as that of pipe, and there are many studies on the principle, method, and application of Lamb wave detection of pipe for reference. Therefore, based...

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“…Ultrasonic guided waves have a large detection range, multimode characteristics, and strong detection ability and can detect structures from long distances and large scales with a small number of sensors [10][11][12] and can be used to select suitable single or multiple blues by adjusting excitation frequency. Ryden and Lowe 13 established the characteristic guided wave equation of a three-layer bonded concrete pavement structure using a global matrix and solved its dispersion curve, which provided theoretical guidance for the nondestructive testing of concrete highways using guided waves.…”

Section: Introductionmentioning

confidence: 99%

Novel method for detection of void defects under track slabs using air-coupled ultrasonic sensors

Chen

Zhu

Fan

et al. 2020

International Journal of Distributed Sensor Networks

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Void defects under track slabs are the main danger affecting the safe operation of high-speed railways. In the short high-speed railway maintenance periods, China’s high-speed railway line maintenance operations must quickly and dynamically determine void defects under track slabs that are in service without contact. However, the detection of void defects under track slabs still mainly relies on the manual inspection and flaw detection by railway workers during the railway maintenance period. If the defects are not quickly identified, the consequences could be disastrous. This article presents a new method for the non-contact dynamic detection of void defects under track slabs. The method involves the use of air-coupled ultrasonic sensors to generate and receive ultrasonic guided waves in the track slab to quantitatively represent the size of the void defect according to the principle of energy leakage of guided waves in the propagation process. The characteristics of the position-amplitude curve, taking the position of the beam axis as the abscissa and the amplitude of the time domain signal as the ordinate, were numerically calculated and analyzed. The quantitative relationship between the convex interval of the position-amplitude curve and the size of the void defect was obtained, and an imaging method of the void defects based on x, y two-dimensional line scanning data fusion is proposed. The excitation and reception methods of air-coupled ultrasonic guided waves were studied, and a 1:1 model of the track structure was built in the laboratory to verify the method and detect the void defect under the track slab. The experimental results show that ultrasonic guided waves can be excited and received in the track slab by air-coupled ultrasonic sensors. Based on the guided wave energy leakage principle, the quantitative characterization and imaging of the void defect under track slabs can be realized.

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Lamb Wave Local Wavenumber Approach for Characterizing Flat Bottom Defects in an Isotropic Thin Plate

Cited by 10 publications

References 39 publications

Sparse-TFM Imaging of Lamb Waves for the Near-Distance Defects in Plate-Like Structures

Sparse-TFM Imaging of Lamb Waves for the Near-Distance Defects in Plate-Like Structures

The Rapid Detection Technology of Lamb Wave for Microcracks in Thin-Walled Tubes

Novel method for detection of void defects under track slabs using air-coupled ultrasonic sensors

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