Comparison of guided and standing waves based full field laser scanning techniques for damage detection using wavenumber analysis (Conference Presentation)

2018 ◽  
Author(s):  
Jun Young Jeon ◽  
Duhwan Kim ◽  
Gyuhae Park ◽  
To Kang ◽  
Soon Woo Han
Keyword(s):  
Damage Detection ◽  
Laser Scanning ◽  
Standing Waves ◽  
Full Field

scholarly journals The Influence of the Grid Density of Measurement Points on Damage Detection in an Isotropic Plate by the Use of Elastic Waves and Laser Scanning Doppler Vibrometry

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7394
Author(s):  
Łukasz Doliński ◽  
Marek Krawczuk ◽  
Magdalena Palacz ◽  
Wiktor Waszkowiak ◽  
Arkadiusz Żak
Keyword(s):  
Damage Detection ◽  
Elastic Waves ◽  
Laser Scanning ◽  
Diagnostic Methods ◽  
Mode Shapes ◽  
Engineering Practice ◽  
Natural Vibrations ◽  
Spectral Finite Element Method ◽  
The Time Domain ◽  
Spectral Finite Element

Damage detection in structural components, especially in mechanical engineering, is an important element of engineering practice. There are many methods of damage detection, in which changes in various parameters caused by the presence of damage are analysed. Recently, methods based on the analysis of changes in dynamic parameters of structures, that is, frequencies or mode shapes of natural vibrations, as well as changes in propagating elastic waves, have been developed at the highest rate. Diagnostic methods based on the elastic wave propagation phenomenon are becoming more and more popular, therefore it is worth focusing on the improvement of the efficiency of these methods. Hence, a question arises about whether it is possible to shorten the required measurement time without affecting the sensitivity of the diagnostic method used. This paper discusses the results of research carried out by the authors in this regard both numerically and experimentally. The numerical analysis has been carried out by the use of the Time-domain Spectral Finite Element Method (TD-SFEM), whereas the experimental part has been based on the measurement performed by 1-D Laser Doppler Scanning Vibrometery (LDSV).

2D-wavelet wavenumber filtering for structural damage detection using full steady-state wavefield laser scanning

2020 ◽  
Vol 116 ◽  
pp. 102343
Author(s):  
Jun Young Jeon ◽  
Duhwan Kim ◽  
Gyuhae Park ◽  
Eric Flynn ◽  
To Kang ◽  
...  
Keyword(s):  
Steady State ◽  
Damage Detection ◽  
Structural Damage ◽  
Laser Scanning ◽  
Structural Damage Detection

scholarly journals Nondestructive Testing of Ceramic Hip Joint Implants with Laser Spot Thermography

2017 ◽  
Vol 62 (4) ◽  
pp. 2133-2139
Author(s):  
J. Roemer ◽  
L. Pieczonka ◽  
M. Juszczyk ◽  
T. Uhl
Keyword(s):  
Damage Detection ◽  
Measurement Techniques ◽  
Infrared Camera ◽  
Field Measurements ◽  
Ceramic Materials ◽  
Test Sample ◽  
Theoretical Background ◽  
Laser Spot ◽  
Signal Acquisition ◽  
Full Field

AbstractThe paper presents an application of laser spot thermography for damage detection in ceramic samples with surface breaking cracks. The measurement technique is an active thermographic approach based on an external heat delivery to a test sample, by means of a laser pulse, and signal acquisition by an infrared camera. Damage detection is based on the analysis of surface temperature distribution near the exciting laser spot. The technique is nondestructive, non-contact and allows for full-field measurements. Surface breaking cracks are a very common type of damage in ceramic materials that are introduced in the manufacturing process or during the service period. This paper briefly discusses theoretical background of laser spot thermography, describes the experimental test rig and signal processing methods involved. Damage detection results obtained with laser spot thermography are compared with reference measurements obtained with vibrothermography. This is a different modality of active thermography, that has been previously proven effective for this type of damage. We demonstrate that both measurement techniques can be effectively used for damage detection and quality control applications of ceramic materials.

Crack Visualization Using Laser-scanning based Guided Ultrasonic and Standing Waves Response Image

2019 ◽  
Vol 39 (6) ◽  
pp. 351-361
Author(s):  
Seong Jin Im ◽  
Jun Young Jeon ◽  
Gyuhae Park ◽  
To Kang ◽  
Soon Woo Han
Keyword(s):  
Laser Scanning ◽  
Standing Waves

scholarly journals Millimeter-Wave Bat for Mapping and Quantifying Micromotions in Full Field of View

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yuyong Xiong ◽  
Songxu Li ◽  
Changzhan Gu ◽  
Guang Meng ◽  
Zhike Peng
Keyword(s):  
Millimeter Wave ◽  
Laser Scanning ◽  
Wide Spectrum ◽  
Mechanical Vibration ◽  
Phase Evolution ◽  
Field Of View ◽  
Vibration Measurement ◽  
Full Field ◽  
Cluttered Environments ◽  
Visual Sensing

Echolocating bats possess remarkable capability of multitarget spatial localization and micromotion sensing in a full field of view (FFOV) even in cluttered environments. Artificial technologies with such capability are highly desirable for various fields. However, current techniques such as visual sensing and laser scanning suffer from numerous fundamental problems. Here, we develop a bioinspired concept of millimeter-wave (mmWave) full-field micromotion sensing, creating a unique mmWave Bat (“mmWBat”), which can map and quantify tiny motions spanning macroscopic to μm length scales of full-field targets simultaneously and accurately. In mmWBat, we show that the micromotions can be measured via the interferometric phase evolution tracking from range-angle joint dimension, integrating with full-field localization and tricky clutter elimination. With our approach, we demonstrate the capacity to solve challenges in three disparate applications: multiperson vital sign monitoring, full-field mechanical vibration measurement, and multiple sound source localization and reconstruction (radiofrequency microphone). Our work could potentially revolutionize full-field micromotion monitoring in a wide spectrum of applications, while may inspiring novel biomimetic wireless sensing systems.

scholarly journals Fast Optical Sectioning for Widefield Fluorescence Mesoscopy with the Mesolens based on HiLo Microscopy

2018 ◽  
Author(s):  
Jan Schniete ◽  
Aimee Franssen ◽  
John Dempster ◽  
Trevor Bushell ◽  
William Bradshaw Amos ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Computation Time ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Optical Sectioning ◽  
Full Field ◽  
Custom Software ◽  
Very Large Datasets ◽  
Acquisition Speed ◽  
Subcellular Resolution

ABSTRACTWe present here a fast optical sectioning method for optical mesoscopy based on HiLo microscopy, which makes possible imaging of specimens of up to 4.4 mm × 3 mm × 3 mm in volume in under 17 hours (estimated for a z-stack comprising 1000 images excluding computation time) with subcellular resolution throughout. Widefield epifluorescence imaging is performed with the Mesolens using a high pixel-number camera capable of sensor-shifting to generate a 259.5 Megapixel image, and we have developed custom software to perform HiLo processing of the very large datasets. Using this method, we obtain comparable sectioning strength to confocal laser scanning microscopy (CLSM), with sections as thin as 6.8±0.2 μm and raw acquisition speed of 1 minute per slice which is up to 30 times faster than CLSM on the full field of view (FOV) of the Mesolens of 4.4 mm with lateral resolution of 0.7 μm and axial resolution of 7 μm. We have applied this HiLo mesoscopy method to image fixed and fluorescently stained hippocampal neuronal specimens and a 5-day old zebrafish larva.

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