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Title: A multi-point laser Doppler vibrometer with fiber-based configuration

Laser Doppler vibrometer (LDV) is a non-contact optical interferometric system to measure vibrations of structures and machines with a high precision. Normal LDV can only offer a single-point measurement. Scanning LDV is usually impractical to do measurement on transient events. In this paper, a fiber-based self-synchronized multi-point LDV is proposed. The multiple laser beams with different frequency shifts are generated from one laser source. The beams are projected onto a vibrating object, reflected and interfered with a common reference beam. The signal including vibration information of multiple spatial points is captured by one single-pixel photodetector. The optical system is mainly integrated by fiber components for flexibility in measurement. Two experiments are conducted to measure a steady-state simple harmonic vibration of a cantilever beam and a transient vibration of a beam clamped at both ends. In the first measurement, a numerical interpolation is applied to reconstruct the mode shape with increased number of data points. The vibration mode obtained is compared with that from FEM simulation. In transient vibration measurement, the first five resonant frequencies are obtained. The results show the new-reported fiber-based multipoint LDV can offer a vibration measurement on various spatial points simultaneously. With the flexibility of fiber configuration,more » it becomes more practical for dynamic structural evaluation in industrial areas.« less
Authors:
 [1] ;  [2] ;  [2] ; ; ; ; ;  [1] ;  [3]
  1. Temasek Laboratories and School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Drive, Singapore 637553 (Singapore)
  2. (China)
  3. Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027 (China)
Publication Date:
OSTI Identifier:
22251237
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 84; Journal Issue: 12; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; BEAMS; CONFIGURATION; FIBERS; FLEXIBILITY; INTERFEROMETERS; INTERPOLATION; LASERS; MECHANICAL VIBRATIONS; OPTICAL SYSTEMS; OSCILLATION MODES; OSCILLATORS