Modal Analysis Using a Virtual Speckle Pattern Based Digital Image Correlation Method: An Application for an Artificial Flapping Wing

Doan, Nguyen Vu; Le, Vinh Tung; Park, H. C.; Goo, Nam Seo

doi:10.1007/s11340-021-00775-w

Cited by 8 publications

(2 citation statements)

References 60 publications

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“…In order to obtain a higher correlation coefficient and improve the accuracy of the digital image correlation method, it is necessary to make a high-quality speckle pattern on the surface of the specimen. The high-quality speckle pattern has the characteristics of aperiodicity, isotropy, high contrast, small speckle radius, high density, uniform gray histogram distribution and high information content [13].…”

Section: Fabrication and Evaluation Of Specklementioning

confidence: 99%

Research on dynamic strain of fan blade based on DIC technology

Liu,

Xu,

Liu

2024

Second International Conference on Electrical, Electronics, and Information Engineering (EEIE 2023)

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When resonance occurs, the blower blades may have large deformation and even cracks, which affects the safety and reliability of its work. The main objective of this study is to abtain the deformation and dynamic strain of small-sized fan blades during vibration experimentally, based on the principle of binocular stereo vision and digital image correlation method, combined with the theory of vibration. The test platform is built by reasonably arranging the test device and calibration device. The speckle pattern on the convex surface of the back of the leaf is made by the point coating method. Using the high-speed image acquisition technology and VIC-3D image processing system, the speckle image of the blade surface during the vibration test is obtained, and the deformation, strain curve and cloud diagram of the blade are analyzed. The results show that the maximum strain of the blade is located at the root of the blade, and its overall strain shows an alternating state with the excitation of sinusoidal vibration. Compared with the strain measured by strain gauge method and the displacement measured by laser vibrometer, the relative errors of strain and displacement measured by VIC-3D are about 4.0% and 3.5%, respectively. The measurement method is easy to operate and has high measurement accuracy, which can provide reference for the strength prediction of fan blades.

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Section: Fabrication and Evaluation Of Specklementioning

confidence: 99%

Research on dynamic strain of fan blade based on DIC technology

Liu,

Xu,

Liu

2024

Second International Conference on Electrical, Electronics, and Information Engineering (EEIE 2023)

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“…The projector and cameras were oriented so that transverse surface movement causes movement of the projected speckle pattern as observed by the cameras. Doan et al [10] expanded on this VSP-DIC method to measure the structural vibrational characteristics of an artificial flapping wing without the need to fabricate an artificial speckle pattern. Using this technique, the first three mode shapes of the wing were obtained (at 57.1 Hz, 143.5 Hz, and 193.4 Hz).…”

Section: Introductionmentioning

confidence: 99%

Off-axis digital image correlation using projected speckles for damage imaging with minimal surface preparation

Abbott,

Yuan

2024

Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XVIII

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This paper presents a feasibility study for the visualization of hidden damage in aluminum plates using the integration of a digital camera, projected speckles, and a baseline-free wavelet transform mode shape curvature (WT-MSC) damage index. To capture out-of-plane motion in the plates, off-axis 2D digital image correlation (DIC) is applied. With the camera at an angle with respect to the plate surface normal, a component of the higher-amplitude transverse displacements can be captured. Compared to 3D DIC, the system is less complex, there is no need for camera calibration, and the 2D DIC algorithm is more computationally efficient. A major limitation of DIC for practical applications is the need to apply a speckle pattern to the surface to introduce trackable features in the image for tracking displacement. Projected speckles replace the need for surface-applied speckle patterns. Thus, minimal surface preparation is required. Two geometrically identical 305-mm ´ 305-mm aluminum plates with thinning defects of different sizes and depths were used to demonstrate the system. Through the excitation of a 20 Hz to 1 kHz chirp signal in a single-edge-clamped plate, the first 12 transverse vibration modes of the plate were sensed. These mode shapes were recreated with the off-axis 2D DIC system, and a wavelet transform mode shape curvature (WT-MSC) damage index was applied for damage imaging. This index is sensitive to irregularities in the higher mode shapes caused by differences in geometry in the damaged regions. The system provided clear damage images with a clear correlation with actual damage geometry regardless of plate orientation. This system serves as a preliminary study for the eventual application of imaging barely visible impact damage in composite plates using projected speckles.

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Experimental Study on Natural Vibration Characteristics of Double-Strip High-Speed Pantograph Head

Zhang

Wei

et al. 2023

Exp Mech

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Modal Analysis Using a Virtual Speckle Pattern Based Digital Image Correlation Method: An Application for an Artificial Flapping Wing

Cited by 8 publications

References 60 publications

Research on dynamic strain of fan blade based on DIC technology

Research on dynamic strain of fan blade based on DIC technology

Off-axis digital image correlation using projected speckles for damage imaging with minimal surface preparation

Experimental Study on Natural Vibration Characteristics of Double-Strip High-Speed Pantograph Head

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