Development and Evaluation of Laser Doppler Techniques for Measurements of Flexural and Longitudinal Structural Intensity
Abstract
Based on the hypothesis that both flexural and longitudinal vibrational energy flow can be measured non-intrusively by an optical technique which can be extended to broadband vibrations, a two-channel laser vibrometer system is developed and evaluated for cross-spectral power flow measurements. The cross-spectral power flow results from tests on small resonant beams and rods are verified by comparison with one-dimensional energetics and standing wave power flow results (obtained with a single scanning laser beam of the two- channel vibrometer). Among the contributions of the thesis are: development and validation of the laser technique for measuring flexural power flow in reverberant fields; introduction of a procedure to maximize phase accuracy which eliminates phase bias error and coherent noise error; an investigation into the differential Doppler method for measuring longitudinal power flow including an analytical model of the effects of bending on the longitudinal power flow measurements; studies of the optical parameters which dictate the performance of the reference beam method and differential Doppler method; and a quantification of how physical and measurement parameters affect the accuracy of this nonintrusive two-point vibrational power flow measurement.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1991
- Accession Number
- ADA242666
Entities
People
- Timothy E. Mcdevitt
Organizations
- Pennsylvania State University