Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"Doppler vibrometer"”.
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Misalignment Effects of the Self-Tracking Laser Doppler Vibrometer
There are many limitations to the current methods used to measure vibration on rotating structures. These limitations include physical flow blockages, relating the measurement spot to the structure rotation, data processing issues, and having to physically alter the engine. This work further …
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Structural energy and power flow using a scanning laser Doppler vibrometer
… method consist of first using a scanning laser Doppler vibrometer (SLDV) to acquire spatially dense measurements of the structure's dynamic response. Second, the continuous 3-D complex-valued velocity field is solved from the laser data. Third, a spatially continuous model of the power is …
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Characterization of laser noise in free-free beam structures using a Scanning Laser Doppler Vibrometer
… dynamics is the use of a Scanning Laser Doppler Vibrometer (SLDV) to measure the dynamic response of vibrating structures. Essential in the optimal use of such a device is an understanding of the idiosyncrasies and operating parameters which may affect the quality of the experimental …
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The estimation and statistical inferences of the position and orientation of a scanning laser Doppler vibrometer
… (position and orientation) of the scanning laser Doppler vibrometer (SLDV) with respect to a structural coordinate system. The parameters in the forward model include the pose and the ranges. The parameters in the inverse model include the pose only. The parameters of those models are obtained by …
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Reconstruction of 3-D structural dynamic response fields: an experimental, laser-based approach with statistical emphasis
… from a set of 3-D projections based on Laser-Doppler-Vibrometer (LDV) localized instantaneous velocity measurements. Included along with an estimate of the 3-D velocity field, are its statistical characteristics and the inferential tools required to test the quality of the estimation. This …
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Development of the Velocity Transformation Function of Damped Flat Shell Finite Element for the Experimental Spatial Dynamics Modeling
… experimental data obtained from a Scanning Laser Doppler Vibrometer (SLDV). In ESDM process, a finite element formulation is used to construct a numerical model of a structure. A conventional finite element such as rod, beam, or plate element, can be used to construct the numerical model of a …
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Three-dimensional velocity extraction using laser Doppler vibrometry
… need to be measured. Now with the use of a Laser Doppler Vibrometer the development of a method to measure three-dimensional velocities has provided the ability to measure in-plane velocities accurately. This thesis outlines the methods used for such three-dimensional extraction and gives an …
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Vehicle Engine Classification Using of Laser Vibrometry Feature Extraction
… as a non-invasive and remote sensor, the laser Doppler vibrometer (LDV) has been used in many different applications, such as inspection of aircrafts, bridge and structure and remote voice acquisition. However, using LDV as a vehicle surveillance device has not been feasible due to the lack of …
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Using a non-modal method for system identification of highly damped and high modal density mechanical structures
… The recent development of the scanning laser Doppler vibrometer (SLDV) technology that provides efficient and massive dynamic data acquisition with high spatial density makes the new non-modal system identification techniques feasible. The proposed non-modal system identification method is …
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Effect of Vibration of Unconsolidated Sand on the Performance of Interferometric Vibration Sensors
… contact sensors are not desired. Laser Doppler vibrometers (LDV) and digital speckle pattern interferometers are studied in this thesis. The working principle of laser Doppler vibrometry and digital shearography is described. The effect of vibration of the unconsolidated sand on the …
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An Experimental Evaluation of the Experimental Spatial Dynamics Modeling (ESDM) Technique
… among such transducers is the scanning laser Doppler vibrometer (LDV). A scanning LDV can measure velocity at many structure locations. An important new technique, Experimental Spatial Dynamics Modeling (ESDM), utilizes such spatially dense velocity data. ESDM models continuous, …
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A Formulation for Updating Finite Element Models Through Consistent Use of Laser Vibrometer Data
… finite element(FE) models using scanning laser Doppler vibrometer(SLDV) dynamic response data. The update formulation is demonstrated in several computer simulations. The formulation is the result of incorporating an analytical FE model into an experimental model. The experimental model …
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A method for the spatial functionalization of the dynamic response of a structure with structural stability considerations
The scanning Laser Doppler Vibrometer (LDV) has developed into a useful tool for rapidly acquiring spatially dense structural dynamic response information in a noncontacting manner. The research presented in this paper is part of a larger project at the Structural Imaging and Modal Analysis …
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Laser-based broad-band spatially dense automated data acquisition system
The scanning laser Doppler vibrometer (SLDV) provides the capability necessary for collecting a broad-band spatially dense data set. A laser-based broad-band spatially dense automated data acquisition system is presented and verified. The motivation for such a system is to provide vibration data at …
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Sensitivity analysis with respect to elastic boundary conditions and laser spatial variables within experimental spatial dynamic modeling
… density data obtained from a scanning laser Doppler vibrometer. Analytical expressions for the first- and second-order error sensitivity of the obtained model with respect to model parameters of the finite element model are developed. A frequency response analysis, resulting in a …
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A study of the wall vibrations excited during the playing of lip-reed instruments
… induced wall vibrations measured using a Laser Doppler Vibrometer. The brass pipe’s natural resonance frequencies and bending mode shapes are established and compared with the velocity amplitude variation along the pipe induced by an artificially blown note. The induced wall vibrations are shown …
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An experimental method for structural intensity and source location
… as tools to study vibrating plates. A laser Doppler vibrometer is used in measuring the plate normal velocity for the calculation of the structural intensity and the force distribution function. Several examples show the possibility of locating sources and studying the influence of ribs and …
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Measurement and analysis of breath sounds
… sounds measurement have been studied: laser Doppler vibrometer and mobile phones. It has been shown that these two methods can find applications in breath sounds measurement, however there are some restrictions. A reliable automatic wheeze detection algorithm based on auditory modelling has …
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Landmine detection with a standoff acoustic/laser technique
… are in turn measured remotely with a Laser Doppler Vibrometer (LDV). In this thesis, the vibration responses of landmine variants are measured, analyzed, and compared to those of common urban objects likely to be found on a landmine field or roadside. The Fourier Transform of the vibration …
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The exploitation of acoustic-to-seismic coupling for the determination of soil properties
… this problem. whilst the novel use of a Laser Doppler Vibrometer has been proposed to provide a completely non-invasive method of measuring motion in soils. The measured coupling ratio has been compared with theoretical predictions, using a modified Bio-Sto11 formulation. The model can be used …
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