scholarly journals Experimental Measurement of Mode Shapes and Frequencies for Vibration of Plates by Optical Interferometry Method

2000 ◽  
Vol 123 (2) ◽  
pp. 276-280 ◽  
Author(s):  
Chi-Hung Huang ◽  
Chien-Ching Ma
Keyword(s):  
Video Recording ◽  
Field Configuration ◽  
Mode Shapes ◽  
Resonant Frequencies ◽  
Full Field ◽  
Out Of Plane ◽  
Vibrating Plates ◽  
Optical Reconstruction ◽  
Fringe Patterns ◽  
Plane Displacement

Most of the published literature for vibration mode shapes of plates is concerned with analytical and numerical results. There are only very few experimental results available for the full field configuration of mode shapes for vibrating plates. In this study, an optical system called the AF-ESPI method with the out-of-plane displacement measurement is employed to investigate experimentally the vibration behavior of square isotropic plates with different boundary conditions. The edges of the plates may either be clamped or free. As compared with the film recording and optical reconstruction procedures used for holographic interferometry, the interferometric fringes of AF-ESPI are produced instantly by a video recording system. Based on the fact that clear fringe patterns will appear only at resonant frequencies, both resonant frequencies and corresponding mode shapes can be obtained experimentally at the same time by the proposed AF-ESPI method. Excellent quality of the interferometric fringe patterns for the mode shapes is demonstrated.

Electronic Speckle Pattern Interferometry Applied to the Displacement Measurement of Sandwich Plates with Single ‘Fully Potted’ Insert

2004 ◽  
Vol 20 (4) ◽  
pp. 273-276 ◽  
Author(s):  
S. J. Huang ◽  
H. L. Lin
Keyword(s):  
Speckle Pattern ◽  
Fem Analysis ◽  
Electronic Speckle Pattern Interferometry ◽  
Sandwich Plates ◽  
Destructive Testing ◽  
Displacement Fields ◽  
Full Field ◽  
Out Of Plane ◽  
Plane Displacement ◽  
Non Destructive

AbstractThe construction and operation of electronic speckle pattern interferometer (ESPI) applied to single-inserted sandwich plates have been earliest presented in this paper. Proposed ESPI has advantages of full-field and non-destructive testing, which can measures microscopic out-of-plane displacement in the elastic region without wasting specimen. For validation purpose, the finite element method (FEM) analysis was conducted. By comparing the results of ESPI and FEM displacement fields around the inserts that a convincing agreement is revealed. The effect of potting material diameter on the displacement of single-inserted sandwich plates was obtained by the ESPI and FEM.

Buckling Analysis of Mindlin Plates Under the Green–Lagrange Strain Hypothesis

2015 ◽  
Vol 15 (06) ◽  
pp. 1450079 ◽  
Author(s):  
Eugenio Ruocco ◽  
Vincenzo Minutolo
Keyword(s):  
Solution Method ◽  
Plate Theory ◽  
Mode Shapes ◽  
Governing Equations ◽  
Nonlinear Strain ◽  
Out Of Plane ◽  
Plates And Shells ◽  
Moderately Thick Plates ◽  
Lagrange Strain ◽  
Plane Displacement

In the present paper, the influence of Green–Lagrange nonlinear strain-displacement terms, usually considered negligible under the von Kármán hypothesis, on the buckling of isotropic, moderately thick plates and shells, is investigated. The first order shear deformation plate theory is applied and the governing equations, containing nonlinear terms related to both in-plane displacement and out-of-plane rotations usually ignored in the literature, are derived using the principle of minimum of the strain energy. The general Levy type solution method is employed, and exact buckling loads and mode shapes are derived. To verify the accuracy of the solution obtained, comparisons with existing data are first made. Then, through graphics and tables, the effect of the nonlinear strain-displacement terms for a range of boundary and load conditions, variations of aspect ratio, thickness ratio and changes in geometry is presented. The results obtained show that the von Kármán's model can sensibly overestimate the critical load for structures characterized by the modes involving comparable in-plane and out-of-plane displacements.

Experimental Investigation on Free Vibration of Foam-Core Sandwich Plate with and without Circular Polymer Columns

2013 ◽  
Vol 845 ◽  
pp. 297-301 ◽  
Author(s):  
Behzad Abdi ◽  
Syed Azwan ◽  
Ayob Amran ◽  
Roslan Abdul Rahman ◽  
R.A. Abdullah
Keyword(s):  
Free Vibration ◽  
Sandwich Plate ◽  
Mode Shapes ◽  
Sandwich Plates ◽  
Vibration Modes ◽  
Foam Core ◽  
Frequency Range ◽  
Resonant Frequencies ◽  
Out Of Plane ◽  
Structure Configuration

Free vibration modes of foam-core sandwich plates with and without polymer columns were experimentally identified from frequency response tests. The responses were made at selected locations on the plate surface by attaching a single-axis accelerometer to measure out-of-plane response. Resonant frequencies, relative damping ratios and mode shapes were established for the lowest 3 out-of-plane modes found in the frequency range of 0-900 Hz. The results show that the vibration characteristics were affected by the sandwich structure configuration and material properties.

Effect of Manufacturing Process on Free Vibration of Foam-Core Sandwich Plate

2013 ◽  
Vol 845 ◽  
pp. 899-903
Author(s):  
Behzad Abdi ◽  
Syed Azwan ◽  
Ayob Amran ◽  
Roslan Abdul Rahman ◽  
Yahya Mohd Yazid
Keyword(s):  
Free Vibration ◽  
Manufacturing Process ◽  
Sandwich Structure ◽  
Sandwich Plate ◽  
Mode Shapes ◽  
Vibration Modes ◽  
Foam Core ◽  
Frequency Range ◽  
Resonant Frequencies ◽  
Out Of Plane

In this paper, the effect of the manufacturing process on free vibration modes of foam-core sandwich plate were experimentally identified from frequency response tests. Three types of foam-core sandwich plate that fabricated by using hand lay-up, vacuum bagging and vacuum infusion process were tested and compared. The responses were made at selected locations on the plate surface by attaching a single-axis accelerometer to measure out-of-plane response. Resonant frequencies, relative damping ratios and mode shapes were established for the lowest 3 out-of-plane modes found in the frequency range of 0-900 Hz. The results show that the vibration characteristics were affected by the fabrication process of the sandwich structure.

Out-of-Plane Displacement Derivative Measurements Using Interferometric Strain/Slope Gage

1996 ◽  
Vol 63 (4) ◽  
pp. 1033-1038 ◽  
Author(s):  
Keyu Li
Keyword(s):  
Coupling Effect ◽  
Controlled System ◽  
High Deformation ◽  
Out Of Plane ◽  
Computer Controlled ◽  
Fringe Patterns ◽  
Photodiode Arrays ◽  
Plane Displacement ◽  
Deformation Gradients ◽  
Derivatives Of

An optical method originally developed for measuring derivatives of in-plane displacements is redefined to measure derivatives of out-of-plane displacements. The technique is based on interference of laser beams reflected and diffracted from two microindentations closely depressed on a specimen surface. As in-plane and out-of-plane displacements cause the microindentations to move relatively to each other, the two interference fringe patterns change accordingly. Movement of the interference fringes is monitored with linear photodiode arrays and analyzed via a computer-controlled system that allows simultaneous measurements of the in-plane and out-of-plane displacement derivatives. The technique is referred to as the interferometric strain/slope gage (ISSG). Having short gage length (˜100 μm), the technique is unique for measurements of high deformation gradients and for applications in complex geometries. Its principle as well as an experimental validation of measuring bending strains/stresses and deflection slopes in a cantilever beam is presented. The experiment shows that both the first-order and second-order derivatives of out-of-plane displacements can be obtained. Measurement sensitivities to in-plane and out-of-plane rigid-body motions are systematically investigated. The technique can be potentially extended to measure large deflection angles. The derived governing equations indicate a coupling effect between the in-plane and out-of-plane components. The associated instrumentation for data acquisition and analysis is described in great detail.

scholarly journals Experimental Investigations on Dynamic Characteristics of a Multilayer Piezoelectric Stack Actuator

2002 ◽  
Vol 18 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Hsien-Yang Lin ◽  
Chien-Ching Ma
Keyword(s):  
Vibration Mode ◽  
Laser Doppler Vibrometer ◽  
Single Layer ◽  
Mode Shapes ◽  
Electronic Speckle Pattern Interferometry ◽  
Experimental Investigations ◽  
Resonant Frequencies ◽  
Fringe Patterns ◽  
Piezoelectric Disc ◽  
Piezoelectric Stack Actuator

AbstractMultilayer piezoelectric stack actuators are widely used in many industrial applications and the investigation on the dynamic behavior of this element is needed. In this study, two optical interferometric techniques called amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) and laser Doppler vibrometer (LDV) are used to experimentally investigate the vibration characteristics of a single-layer piezoelectric disc and a multilayer piezoelectric stack actuator. These two techniques are full-field measurement for AF-ESPI and point-wise displacement measurement for LDV. Because the clear fringe patterns obtained by the AF-ESPI method will be shown only at resonant frequencies, both the resonant frequencies and corresponding vibration mode shapes of the piezoelectric disc and the multilayer piezoelectric stack actuator are obtained simultaneously by the AF-ESPI method. Interferometric fringe patterns for both the in-plane and out-of-plane vibration mode shapes are demonstrated. In addition to the proposed two optical techniques, numerical computations based on a commercially available finite element package are presented for comparison with the experimental results. Good agreement between the measured data by experimental methods and the numerical results predicted by FEM is found in resonant frequencies and mode shapes for the single-layer piezoelectric disc. However, some discrepancies are observed for the results obtained by AF-ESPI and impedance analysis for the multilayer piezoelectric stack actuator. A detailed discussion is made to address important issues of this problem.

scholarly journals Electronic Speckle Pattern Interferometry for Vibrational Analysis of Cutting Tools

2018 ◽  
Vol 12 (2) ◽  
pp. 135-140
Author(s):  
Piotr Mrozek ◽  
Ewa Mrozek ◽  
Andrzej Werner
Keyword(s):  
Speckle Pattern ◽  
Laser System ◽  
Michelson Interferometer ◽  
Cutting Tools ◽  
Vibrational Analysis ◽  
Mode Shapes ◽  
Electronic Speckle Pattern Interferometry ◽  
Measurement Methodology ◽  
Fringe Patterns ◽  
Plane Displacement

Abstract A Michelson interferometer based ESPI system for static and vibration out of plane displacement measurements is presented. The aim of the article is to demonstrate the usability of ESPI non-contact measurement method in the field of machining. The correlation fringe patterns were visualized using custom software. The accuracy of ESPI interferometer was verified by the comparison with measurement results collected using industrial XL-80 laser system. The efficacy in vibration analysis was tested by studying the mode shapes and resonant frequencies of the transverse vibrations of square plates. The measurement methodology was used to determine natural frequencies and the shapes of vibrational modes of NFTe 100x1.2/64-II circular slitting saw. As a result the values of rotational speed that should be avoided during machining were determined.

Quality Inspection of Flip Chip Solder Bumps Using Integrated Analytical, Numerical, and Experimental Modal Analyses

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Jin Yang ◽  
I. Charles Ume
Keyword(s):  
Modal Analysis ◽  
Manufacturing Industry ◽  
Flip Chip ◽  
Solder Bump ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Inspection System ◽  
Solder Bumps ◽  
Out Of Plane ◽  
Plane Displacement

Solder bump inspection of surface mount packages has been a crucial process in the electronics manufacturing industry. A solder bump inspection system has been developed using laser ultrasound and interferometric techniques. In this research, modal analysis is important to correlate the defects with dynamic responses of packaged electronic devices under pulsed laser loading. The effect of solder bump defects on the mode frequencies and mode shapes is reported in this paper. The objective is to develop a modal analysis approach, which integrates analytical, numerical, and experimental methods. In particular, this paper discusses the analytical modeling, numerical modeling, and transient out-of-plane displacement measurements for a 6.35×6.35×0.6mm3 PB18 flip chip mounted on a FR4 board.

Effect of general boundary and coupling conditions on the vibration and power flow characteristics of a coupled H-shaped three-plate structure

2019 ◽  
Vol 50 (9-11) ◽  
pp. 291-305
Author(s):  
Kavikant Mahapatra ◽  
SK Panigrahi
Keyword(s):  
Power Flow ◽  
Flow Characteristics ◽  
Coupled System ◽  
Mode Shapes ◽  
Plate Structures ◽  
Coupling Conditions ◽  
Out Of Plane ◽  
Coupling Stiffness ◽  
Plane Displacement ◽  
Plate System

Coupled H-shaped three-plate structures are extensively used as support platforms for machinery structures in engineering applications. These structures are constructed with various types of real engineering boundaries and coupling mechanisms. This investigation presents a numerical analysis of the effect of finitely varying boundary and coupling conditions on the vibration and power flow characteristics of a coupled H-shaped three-plate system. Modified Fourier series approximation of out-of-plane and in-plane displacement along with the Rayleigh–Ritz energy minimising procedure has been utilised for theoretical analysis, and different cases of variation of boundary and coupling spring stiffnesses have been taken to numerically analyse its effect on the vibration and power flow characteristics of the plate system. The numerical results indicate the presence of three different zones of finite coupling stiffness combinations at the coupled junction wherein the natural frequency and mode shapes undergo a major alteration. The decay or amplification of power flow characteristics across the plate junctions has been found to be highly dependent on the coupling stiffness values at the junctions. The consideration of general boundaries and coupling conditions in coupled plate systems is an essential design necessity for accurate prediction of the dynamic behaviour of coupled plate structures as their finite variations greatly influence the vibration and power flow characteristics of the coupled system.

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