scholarly journals Digital Double-Pulse Holographic Interferometry for Vibration Analysis

1996 ◽  
Vol 3 (2) ◽  
pp. 117-125
Author(s):  
H.J. Tiziani ◽  
G. Pedrini
Keyword(s):  
Holographic Interferometry ◽  
Vibration Analysis ◽  
Speckle Pattern ◽  
Ccd Camera ◽  
Image Plane ◽  
Speckle Interferometry ◽  
Electronic Speckle Pattern Interferometry ◽  
3 Dimensional ◽  
Digital Reconstruction ◽  
Fitting Method

Different arrangements for double-pulsed holographic and speckle interferometry for vibration analysis will be described. Experimental results obtained with films (classical holographic interferometry) and CCD cameras (digital holographic interferometry) as storage materials are presented. In digital holography, two separate holograms of an object under test are recorded within a few microseconds using a CCD camera and are stored in a frame grabber. The phases of the two reconstructed wave fields are calculated from the complex amplitudes. The deformation is obtained from the phase difference. In the case of electronic speckle pattern interferometry (or image plane hologram), the phase can be calculated by using the sinusoid-fitting method. In the case of digital holographic interferometry, the phase is obtained by digital reconstruction of the complex amplitudes of the wave fronts. Using three directions of illumination and one direction of observation, all the information necessary for the reconstruction of the 3-dimensional deformation vector can be recorded at the same time. Applications of the method for measuring rotating objects are discussed where a derotator needs to be used.

Application of ESPI in the Vibration Analysis of Turbine Blading

1995 ◽  
Author(s):  
Robert X. Wang ◽  
Graham M. Chapman
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Vibration Analysis ◽  
Speckle Pattern ◽  
Vibration Measurement ◽  
Simplified Model ◽  
Electronic Speckle Pattern Interferometry ◽  
Coupled Modes ◽  
Element Analysis ◽  
Turbine Blading

Abstract This paper reports on the application of Electronic Speckle Pattern Interferometry (ESPI) technique in vibration measurement of turbine blading. Using the time-averaged mode of ESPI, the first six modes of a turbocharger blade with airfoil profile were identified. The effect of the complicated profile of the blade was established by studying simplified model blades. Coupled modes were identified and successfully separated. Experimental results are compared with those obtained using finite element analysis.

Cantilevered Plate Vibration Analysis Based on Electronic Speckle Pattern Interferometry and Digital Shearing Speckle Pattern Interferometry

2019 ◽  
Vol 39 (4) ◽  
pp. 0403001
Author(s):  
马银行 Ma Yinhang ◽  
蒋汉阳 Jiang Hanyang ◽  
戴美玲 Dai Meiling ◽  
代祥俊 Dai Xiangjun ◽  
杨福俊 Yang Fujun
Keyword(s):  
Vibration Analysis ◽  
Speckle Pattern ◽  
Electronic Speckle Pattern Interferometry ◽  
Plate Vibration ◽  
Cantilevered Plate

Developments In Electronic Speckle Pattern Interferometry For Automotive Vibration Analysis.

1988 ◽  
Author(s):  
Jeremy C. Davies ◽  
Clive H. Buckberry ◽  
Julian D. C. Jones ◽  
Chris N. Pannell
Keyword(s):  
Vibration Analysis ◽  
Speckle Pattern ◽  
Electronic Speckle Pattern Interferometry

Damage Location Assessment in a Composite Panel by Means of Electronic Speckle Pattern Interferometry Measurements

2005 ◽  
Author(s):  
Alessandro Zanarini
Keyword(s):  
Structural Damage ◽  
Speckle Pattern ◽  
Harmonic Excitation ◽  
Speckle Interferometry ◽  
Composite Panel ◽  
Electronic Speckle Pattern Interferometry ◽  
Full Field ◽  
Damage Location ◽  
Displacement Maps ◽  
Non Destructive

The assessment of structural damage location in composite honeycomb sandwich panels is here pursued by means of a complete experimental non-destructive approach on a pre-damaged sample. In the experiments proposed full field displacement maps were acquired by means of optical non-contact Electronic Speckle Pattern Interferometry (ESPI) technology [1, 2], in order to obtain high spatial definition and locate small defects on the sample, like debondings, material separations, voids, cracks and delaminations. When dealing with holographic/speckle interferometry it is important to find the stressing technique able to produce singularities in the state of the object surface. Four different loading approaches were taken to detect the flaws: acoustic, thermal, static and harmonic excitation. The displacement maps acquired depict with high accuracy the inhomogeneous local behavior of the structure induced by the defects. Results are reported from the different loading approaches and discussed in detail.

Determination of the Regional Function of the Heart

2002 ◽  
Author(s):  
Evren U. Azeloglu ◽  
Glenn R. Gaudette ◽  
Irvin B. Krukenkamp ◽  
Fu-Pen Chiang
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Speckle Pattern ◽  
Strain Tensor ◽  
Ccd Camera ◽  
Speckle Interferometry ◽  
Left Ventricular ◽  
Stroke Work ◽  
Regional Function

Unlike many other engineering designs, the heart, a pressure vessel, shows variations within its chambers and surface in terms of mechanical function. This necessitates a whole field technique with high spatial resolution. Computer aided speckle interferometry (CASI), a nondestructive examination technique, is herein developed for this purpose. A speckle pattern was created on the surface of isolated rabbit hearts. Images of the beating hearts werc acquired with a charge-couple device (CCD) camera for one second at a rate of 50 frames per second. CASI was used to determine the 2-D displacement vectors over regions of approximately 4 × 6 mm. Regional area stroke work (the integral of the left ventricular pressure with respect to area), the first invariant of the 2-D strain tensor, and the principle strains were used to determine the regional function. After occluding the blood supply to a region of the heart, significant changes were detected in all the previously mentioned parameters. Commonly used techniques cannot determine 2-D strain and lack the high spatial resolution of CASI. Determination of the 2-D strain can provide useful data on the functionality of the heart.

Vibration Control in Turbomachinery Blading Using Lacing Wires

1995 ◽  
Author(s):  
Robert X. Wang ◽  
Graham M. Chapman
Keyword(s):  
Finite Element ◽  
Vibration Control ◽  
Dynamic Characteristics ◽  
Vibration Analysis ◽  
Finite Element Modelling ◽  
Speckle Pattern ◽  
Electronic Speckle Pattern Interferometry ◽  
Element Modelling ◽  
Wire Vibration ◽  
Theoretical Results

Abstract In turbomachinery practice the use of inter-blade coupling is an accepted procedure. The use of lacing wires in highly stressed short blading introduces damping and also modifies the vibration characteristics of the blading. This paper reports on a study into the dynamic characteristics of single blades with a lacing wire. Vibration analysis is carried out using finite element modelling. The theoretical results are verified using Electronic Speckle Pattern Interferometry technique (ESPI).

scholarly journals An Experimental Study of the Vibrational Characteristics of a Diamond Circular Blade Using Electronic Speckle-Pattern Interferometry and FEM

2021 ◽  
Vol 15 (1) ◽  
pp. 16-23
Author(s):  
Mykhaylo Tkach ◽  
Yurii Halynkin ◽  
Arkadii Proskurin ◽  
Irina Zhuk ◽  
Volodymyr Kluchnyk ◽  
...  
Keyword(s):  
Mean Squared Error ◽  
Speckle Pattern ◽  
Speckle Interferometry ◽  
Mode Shapes ◽  
Electronic Speckle Pattern Interferometry ◽  
Minimum Mean Squared Error ◽  
Program Calculation ◽  
Vibrational Characteristics ◽  
Electronic Speckle Interferometry ◽  
Inner Diameter

Abstract The compact installation and technology for determining vibration characteristics by the ESPI method has been created. The experimental determination of the dynamic characteristics of a diamond circular blade with a diameter of 203.4 mm and a thickness of 1.19 mm using real-time electronic speckle interferometry is presented. 15 mode shapes of vibration were detected in the range from 100 to 5000 Hz. The program calculation of the natural frequencies and mode shapes is carried out for three values of the clamping inner diameter (42 mm, 44 mm, 46 mm). The options for calculating a disk with a rim and without a rim are considered. It is shown that the minimum mean squared error of the calculation is achieved for the values of the diameter of the disk 46 mm, 42 mm and 44 mm for the number of nodal circles 0, 1 and 2, respectively. To verify the accuracy of the interferometer, experimental, computational and analytical studies of console steel rod 200 × 22.25 × 3.78 mm in size were carried out.

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