Quasi-OCVT technique for response-only experimental modal analysis of beam-like structures

Abstract

An optical measurement system, which is capable of vibration measurement and response-only experimental modal analysis for beam-like structures, is reported by taking the concept of 2-dimensional optical coherence vibration tomography technique. In the proposed approach, it requires only quasi-interferogram fringe patterns as sensors and a high-speed camera as a detector. Experimental results of beam-like structures subjected to swept and harmonic excitations are demonstrated. The key advantage of the proposed method is the high spatial and temporal resolution with simultaneously measuring the absolute displacement of multiple points along the beam-like structures without point-by-point optical scanning. Without any vibration excitation information, the quasi-optical coherence vibration tomography technique system can capture structural modal parameters. Therefore, it is a response-only experimental modal analysis method, making it attractive for the structural health monitoring applications in the multiple-point measurement of real engineering structures with the absence of vibration input information.