Comparative Study of High-Speed Digital Holographic Interferometry and Scanning Laser Doppler Vibrometry for Modal Analysis

High-speed digital holographic interferometry (DHI) and scanning laser Doppler vibrometry (SLDV) are optical full field-of-view (FOV) methods for measurement of dynamic deformations. In this paper, we present and discuss a comparative study of the performance between the two methods as applied to experimental modal analysis. The designed experimental procedure uses a highly repeatable metallic turbine blade stimulated by 25 kHz bandwidth excitation signals using piezoelectric shakers. As part of the comparison analysis, measurement acquisition time consumptions, errors and deviations for response magnitudes, frequencies, and damping parameters are studied. We report advantages and disadvantages of each method and the suitability of each technique in various applications.