Single beam method for three-axial vibration measurement

摘要

Measurement of structural dynamics is used for dynamic characterization, diagnostics, condition monitoring, vibration problem analysis, design optimization and as comparison data to improve computation results. Most often three dimensional measurements are required on all relevant structure points. Two main vibration measurement principles dominate the experimental modal analysis. Laser vibrometers used as a three-beam device are applied for open surfaces measurements e.g. in automotive and aerospace industries. Three-axial accelerometers are mainly used where the laser vibrometers are not applicable due to difficulties with the line-of-sight in partly housed structures, narrow spaces, or simply due to high system costs. This paper introduces a novel approach for three-axial vibration measurement using a single laser beam device equipped with an interferometer and a position sensitive photodiode. The measurement principle is introduced, vibration measurement results together with a brief benchmark against traditional devices is carried out. A complete modal analysis of a machine tool with comparison to accelerometer measurements is presented. A research of measurement uncertainties and possible measurement errors is presented.