High Speed Digital Holography: Equivalence of Full-Field Accelerometer for Vibration Measurement

1996 ◽  
Author(s):  
Y. Y. Hung ◽  
C. T. Griffen ◽  
F. Chen
Keyword(s):  
High Speed ◽  
Digital Holography ◽  
Vibration Measurement ◽  
Full Field

Full-Field Laser Vibrometer for Instantaneous Vibration Measurement and Non-Destructive Inspection

2010 ◽  
Vol 437 ◽  
pp. 407-411 ◽  
Author(s):  
James M. Kilpatrick ◽  
Vladimir B. Markov
Keyword(s):  
High Speed ◽  
Fiber Optic ◽  
Speckle Pattern ◽  
Vibration Measurement ◽  
Electronic Speckle Pattern Interferometry ◽  
Laser Vibrometer ◽  
Full Field ◽  
The Matrix ◽  
Interferometric Sensor ◽  
Non Destructive

We describe a system for real-time, full-field vibrometry, incorporating features of high-speed electronic speckle pattern interferometry (ESPI) and laser Doppler velocimetry (LDV). Based on a 2D interferometric sensor array, comprising 16×16 parallel illumination and detection channels, the matrix laser vibrometer (MLV), captures full-field data instantaneously, without beam scanning. The instrument design draws on the advantages of scale offered by modern telecommunications fiber optic and digital electronics. The resulting architecture, comprising a compact measurement probe linked by fiber optic umbilical to a remote electronics unit, facilitates practical application to the full-field study of transient vibrations and rapid non-destructive inspection of composite materials.

High Speed Digital Holography for Measuring Time-Dependent Displacement and Vibrations

1995 ◽  
Author(s):  
Y. Y. Hung ◽  
C. T. Griffen
Keyword(s):  
High Speed ◽  
Digital Holography ◽  
Time Dependent ◽  
Vibration Measurement ◽  
Measuring Time ◽  
Novel Technique ◽  
Point Of Interest ◽  
Displacement Sensors ◽  
Image Acquisition System ◽  
Fringe Patterns

Abstract This paper presents a novel technique allowing time-dependent displacement of an object to be studied by continuously digitizing the speckle images using a high speed image acquisition system. Instead of generating fringe patterns, the displacement versus time for any point of interest can be studied. Therefore, the technique is equivalent to “many” massless and noncontact displacement sensors, which is particularly useful for vibration measurement.

Full-field force identification with high-speed digital holography

2022 ◽  
Vol 164 ◽  
pp. 108215
Author(s):  
Erwan Meteyer ◽  
Felix Foucart ◽  
Mathieu Secail-Geraud ◽  
Pascal Picart ◽  
Charles Pezerat
Keyword(s):  
High Speed ◽  
Digital Holography ◽  
Force Identification ◽  
Full Field ◽  
Field Force

scholarly journals Recent advances in speckle decorrelation modeling and processing in digital holographic interferometry

2021 ◽  
Vol 13 (4) ◽  
pp. 73
Author(s):  
Pascal Picart
Keyword(s):  
Deep Learning ◽  
Holographic Interferometry ◽  
High Speed ◽  
Digital Holography ◽  
Speckle Noise ◽  
Noise Removal ◽  
Surface Shape ◽  
Full Field ◽  
Recent Advances ◽  
Phase Data

Digital holography, and especially digital holographic interferometry, is a powerful approach for the characterization of modifications at the surface or in the volume of objects. Nevertheless, the reconstructed phase data from holographic interferometry is corrupted by the speckle noise. In this paper, we discuss on recent advances in speckle decorrelation noise removal. Two main topics are considered. The first one presents recent results in modelling the decorrelation noise in digital Fresnel holography. Especially the anisotropy of the decorrelation noise is established. The second topic presents a new approach for speckle de-noising using deep convolution neural networks. Full Text: PDF ReferencesP. Picart (ed.), New techniques in digital holography (John Wiley & Sons, 2015). CrossRef T.M. Biewer, J.C. Sawyer, C.D. Smith, C.E. Thomas, "Dual laser holography for in situ measurement of plasma facing component erosion (invited)", Rev. Sci. Instr. 89, 10J123 (2018). CrossRef M. Fratz, T. Beckmann, J. Anders, A. Bertz, M. Bayer, T. Gießler, C. Nemeth, D. Carl, "Inline application of digital holography [Invited]", Appl. Opt. 58(34), G120 (2019). CrossRef M.P. Georges, J.-F. Vandenrijt, C. Thizy, Y. Stockman, P. Queeckers, F. Dubois, D. Doyle, "Digital holographic interferometry with CO2 lasers and diffuse illumination applied to large space reflector metrology [Invited]", Appl. Opt. 52(1), A102 (2013). CrossRef E. Meteyer, F. Foucart, M. Secail-Geraud, P. Picart, C. Pezerat, "Full-field force identification with high-speed digital holography", Mech. Syst. Signal Process. 164 (2022). CrossRef L. Lagny, M. Secail-Geraud, J. Le Meur, S. Montresor, K. Heggarty, C. Pezerat, P. Picart, "Visualization of travelling waves propagating in a plate equipped with 2D ABH using wide-field holographic vibrometry", J. Sound Vib. 461 114925 (2019). CrossRef L. Valzania, Y. Zhao, L. Rong, D. Wang, M. Georges, E. Hack, P. Zolliker, "THz coherent lensless imaging", Appl. Opt. 58, G256 (2019). CrossRef V. Bianco, P. Memmolo, M. Leo, S. Montresor, C. Distante, M. Paturzo, P. Picart, B. Javidi, P. Ferraro, "Strategies for reducing speckle noise in digital holography", Light: Sci. Appl. 7(1), 1 (2018). CrossRef V. Bianco, P. Memmolo, M. Paturzo, A. Finizio, B. Javidi, P. Ferraro, "Quasi noise-free digital holography", Light. Sci. Appl. 5(9), e16142 (2016). CrossRef R. Horisaki, R. Takagi, J. Tanida, "Deep-learning-generated holography", Appl. Opt. 57(14), 3859 (2018). CrossRef E. Meteyer, F. Foucart, C. Pezerat, P. Picart, "Modeling of speckle decorrelation in digital Fresnel holographic interferometry", Opt. Expr. 29(22), 36180 (2021). CrossRef M. Piniard, B. Sorrente, G. Hug, P. Picart, "Theoretical analysis of surface-shape-induced decorrelation noise in multi-wavelength digital holography", Opt. Expr. 29(10), 14720 (2021). CrossRef P. Picart, S. Montresor, O. Sakharuk, L. Muravsky, "Refocus criterion based on maximization of the coherence factor in digital three-wavelength holographic interferometry", Opt. Lett. 42(2), 275 (2017). CrossRef P. Picart, J. Leval, "General theoretical formulation of image formation in digital Fresnel holography", J. Opt. Soc. Am. A 25, 1744 (2008). CrossRef S. Montresor, P. Picart, "Quantitative appraisal for noise reduction in digital holographic phase imaging", Opt. Expr. 24(13), 14322 (2016). CrossRef S. Montresor, M. Tahon, A. Laurent, P. Picart, "Computational de-noising based on deep learning for phase data in digital holographic interferometry", APL Photonics 5(3), 030802 (2020). CrossRef M. Tahon, S. Montresor, P. Picart, "Towards Reduced CNNs for De-Noising Phase Images Corrupted with Speckle Noise", Photonics 8(7), 255 (2021). CrossRef E. Meteyer, S. Montresor, F. Foucart, J. Le Meur, K. Heggarty, C. Pezerat, P. Picart, "Lock-in vibration retrieval based on high-speed full-field coherent imaging", Sci. Rep. 11(1), 1 (2021). CrossRef

Detecting Vibration Problems in Machines and Structures Using Motion Capturing by Camera

2021 ◽  
Vol 21 (1) ◽  
pp. 38-49
Author(s):  
Husam Sattar Jasim ◽  
Jaafar Khalaf Ali
Keyword(s):  
High Speed ◽  
Low Cost ◽  
Vibration Signal ◽  
Vibration Measurement ◽  
High Speed Camera ◽  
Full Field ◽  
Phase Angle Difference ◽  
Vibration Data ◽  
Vibration Sensors ◽  
The Time Domain

Vibration in rotating machines and structures is normally measured using accelerometers and other vibration sensors. For large machines and structures, the process of collecting vibration data is tedious and time-consuming due to the large number of points where vibration data must be measured. In this paper, a novel non-contact vibration measurement method has been introduced by using a high-speed camera as a vibration measurement device. This method has many advantages compared with the others. It has a low cost, easy to setup, and high automation. It also can be used for full-field measurement. Many tests have been accomplished to prove the validation of this method. The verification test has been accomplished by using the machinery faults simulator. It presented a reasonable validation that the operation deflection shapes (ODS) and the phase difference of any object can be successfully measured by using a high-speed camera. The mode shape tests have been accomplished by using the whirling of shaft apparatus device to extract the time domain, frequency domain, ODS, and phase differences for many points on the shaft at the first two critical speeds. The results proved that the high-speed camera can be used to detect the vibration signal in many different fault cases. It also proved that the high-speed camera can be used to detect the ODS and the phase angle difference. That gives the proposed method more robust and acceptance.

scholarly journals Full-Field Operational Modal Analysis of an Aircraft Composite Panel from the Dynamic Response in Multi-Impact Test

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1602
Author(s):  
Ángel Molina-Viedma ◽  
Elías López-Alba ◽  
Luis Felipe-Sesé ◽  
Francisco Díaz
Keyword(s):  
Modal Analysis ◽  
Energy Absorption ◽  
High Speed ◽  
Operational Modal Analysis ◽  
Modal Identification ◽  
Image Correlation ◽  
Composite Panel ◽  
Impact Excitation ◽  
Full Field ◽  
The Impact

Experimental characterization and validation of skin components in aircraft entails multiple evaluations (structural, aerodynamic, acoustic, etc.) and expensive campaigns. They require different rigs and equipment to perform the necessary tests. Two of the main dynamic characterizations include the energy absorption under impact forcing and the identification of modal parameters through the vibration response under any broadband excitation, which also includes impacts. This work exploits the response of a stiffened aircraft composite panel submitted to a multi-impact excitation, which is intended for impact and energy absorption analysis. Based on the high stiffness of composite materials, the study worked under the assumption that the global response to the multi-impact excitation is linear with small strains, neglecting the nonlinear behavior produced by local damage generation. Then, modal identification could be performed. The vibration after the impact was measured by high-speed 3D digital image correlation and employed for full-field operational modal analysis. Multiple modes were characterized in a wide spectrum, exploiting the advantages of the full-field noninvasive techniques. These results described a consistent modal behavior of the panel along with good indicators of mode separation given by the auto modal assurance criterion (Auto-MAC). Hence, it illustrates the possibility of performing these dynamic characterizations in a single test, offering additional information while reducing time and investment during the validation of these structures.

An improved model for investigating the vibration characteristics of ball bearing owing to outer race waviness under high speed

2021 ◽  
Vol 69 (2) ◽  
pp. 89-101
Author(s):  
Pingping Hou ◽  
Liqin Wang ◽  
Zhijie Xie ◽  
Qiuyang Peng
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Vibration Measurement ◽  
Vibration Frequencies ◽  
Outer Race ◽  
Response Characteristics ◽  
Lagrange’S Equation ◽  
Rolling Elements ◽  
Initial Clearance ◽  
Improved Model

In this study, an improved model for a ball bearing is established to investigate the vibration response characteristics owing to outer race waviness under an axial load and high speed. The mathematical ball bearing model involves the motions of the inner ring, outer ring, and rolling elements in the radial XY plane and axial z direction. The 2Nb + 5 nonlinear differential governing equations of the ball bearing are derived from Lagrange's equation. The influence of rotational speed and outer race waviness is considered. The outer race waviness is modeled as a superposition of sinusoidal function and affects both the contact deformation between the outer raceway and rolling elements and initial clearance. The MATLAB stiff solver ODE is utilized to solve the differential equations. The simulated results show that the axial vibration frequency occurred at l fc and the radial vibration frequencies appeared at l fc fc when the outer race waviness of the order (l) was the multiple of the number of rolling elements (k Nb) and that the principal vibration frequencies were observed at l fc fc in the radial x direction when the outer race waviness of the order (l) was one higher or one lower than the multiple of the number of rolling elements (k Nb 1). At last, the validity of the proposed ball bearing model was verified by the high-speed vibration measurement tests of ball bearings.

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