Application of Laser Vibrometry to Vibration Measurement on Rotating Components

1995 ◽  
Author(s):  
Steven J. Rothberg ◽  
Neil A. Halliwell
Keyword(s):  
Vibration Analysis ◽  
Laser Speckle ◽  
Vibration Measurement ◽  
Torsional Vibrations ◽  
Radial Vibration ◽  
Laser Vibrometry ◽  
Laser Doppler Vibrometry ◽  
Vibration Measurements ◽  
Speed Fluctuations ◽  
Fundamental Limitation

Abstract This paper describes the application of Laser Doppler Vibrometry to vibration measurements on rotating targets. The noise generating mechanism of the laser speckle phenomenon is first explained before confirmation of the insensitivity of measurements to target shape. The principal focus of the paper is on the fundamental limitation associated with the use of Laser Vibrometers for radial vibration measurements directly on rotating components. In such measurements significant cross-sensitivities to speed fluctuations, including torsional vibrations, and in-plane vibrations are evident, preventing synchronous vibration analysis. Mathematical and electronic means to resolve the correct orthogonal vibration components are presented and shown to be successful in enabling the use of Laser Vibrometry for non-synchronous vibration measurements.

Vibration Measurements on Rotating Machinery Using Laser Doppler Velocimetry

1994 ◽  
Vol 116 (3) ◽  
pp. 326-331 ◽  
Author(s):  
S. J. Rothberg ◽  
N. A. Halliwell
Keyword(s):  
Velocity Component ◽  
Laser Doppler Velocimetry ◽  
Rotating Machinery ◽  
Vibration Measurement ◽  
Surface Velocity ◽  
Laser Vibrometer ◽  
Doppler Velocimetry ◽  
Laser Vibrometry ◽  
Vibration Measurements ◽  
Measurement Direction

This paper explores the use of laser vibrometry for vibration measurement directly from a rotating component. The presence of a surface velocity component due to the rotation itself is shown to create a strong measurement dependency on vibration perpendicular to the intended measurement direction. Particular ambiguity results at synchronous frequencies. A mathematical means to resolve the genuine vibration components from two simultaneous laser vibrometer measurements is presented and shown to be effective in the study of nonsynchronous rotor vibrations.

Vibration Analysis of ID Slicing Process and Wafer Measurement

2006 ◽  
Vol 315-316 ◽  
pp. 641-645 ◽  
Author(s):  
Xin Wei ◽  
Rui Wei Huang ◽  
Shao Hui Lai ◽  
Z.H. Xie
Keyword(s):  
Surface Roughness ◽  
Power Spectrum ◽  
Vibration Analysis ◽  
Machining Accuracy ◽  
Radial Vibration ◽  
Total Thickness ◽  
Axial Vibration ◽  
Vibration Signals ◽  
Measurement And Analysis ◽  
Inner Diameter

ID (inner-diameter) slicing is widely used in cutting ingots currently. In this paper, the deflection (axial vibration) and vibration (radial vibration) signals in different slicing conditions of the silicon wafers were measured online and analyzed. The effects of the vibration signals on the machining accuracy and surface roughness of sliced wafers were investigated based on the measurement and analysis of the surface roughness, warpage and TTV (total thickness vibration) of the sliced wafers. The results show that the changes of surface roughness, warpage and TTV of the sliced wafers exhibit approximately consistence with the changes of the power spectrums of the acquired vibration signals in different working stage of the blade. The vibration and deflection signals can give evidence of the changes in the cutting forces and blade performance during slicing. The power spectrum of the signals is useful for monitoring the blade wear and tension condition and predicting the surface quality and machining accuracy of the sliced wafers.

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.

Performance Based Evaluation of Bridge Substructure in North Mississippi Using Nonlinear FEM and Field Vibration Measurement

2000 ◽  
Author(s):  
Chris L. Mullen ◽  
Prabin R. Tuladhar
Keyword(s):  
Finite Element ◽  
Transfer Functions ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Vibration Measurement ◽  
Elastic Behavior ◽  
Evaluation Procedure ◽  
Vibration Measurements ◽  
Linear Elastic ◽  
Performance Based Evaluation

Abstract Discussion of a Performance - Based Engineering evaluation procedure for an existing interstate highway bridge in north Mississippi. The bridge is in a highly trafficked location near the Memphis Metropolitan area and is reflective of modern design practices in Mississippi. Results are presented of nonlinear damage response and displacement ductility performance of the reinforced concrete bents and their foundations predicted using static finite element (FE) computations. The model considers the composite action of the concrete and the reinforcing steel materials under axial force, shear, torsion and flexure. The performance-based evaluation includes three-dimensional computational simulations of the nonlinear bridge system, including substructures and superstructure. The response spectrum dynamic analysis method will also be carried out on the linear elastic three-dimensional model to predict the linear elastic behavior. Field vibration measurements, including ambient and hammer-impact, were performed to calibrate the models. The computed transfer functions are currently being evaluated to correlate vibration measurements and the Finite element models.

A New Dual-Channel Analyzer for Vibration of Rotary Machine

2008 ◽  
Author(s):  
Qing He ◽  
Dongmei Du
Keyword(s):  
Vibration Analysis ◽  
High Speed ◽  
Integral Transform ◽  
Vibration Measurement ◽  
Waveform Analysis ◽  
Rotating Speed ◽  
Rotary Machine ◽  
Vibration Sensors ◽  
Dual Channel ◽  
Channel Analyzer

A new simultaneous sampling and analyzer for dual-channel signal of vibration for rotating machine is developed based on the C8051F060, which is a high-speed SoC system and has two ADCs embedded with high sampling frequency. The signal condition circuits for various vibration sensors are designed, such as charge amplifier, integral transform and rotating speed detector. A colorful TFT LCD used can display all kinds of vibration analysis plots that are friendly in human-machine interface. The large capability non-volatile memory is used to restore up to one hundred of group of vibration waves. With many typical functions of vibration analysis, including waveform analysis, spectrum, orbit and balancing, this instrument is widely applied to vibration measurement and fault diagnosis of machine and equipment, especially for field balancing of rotary machine.

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