The CSLDV Technique for Vibration Measurement of a Plate Structure with Arbitrary Rectangular Holes

Abstract

The Continuous Scanning Laser Doppler Vibrometry (CSLDV) developed on the base of the galvanometer scanner system has made it possible to quickly obtain the full-field vibration responses within an intact structure without any hole. In order to make CSLDV also suitable for testing structures with arbitrary rectangular holes, a novel method of area-partitioned continuous scanning test and mode reconstruction is further proposed in this paper. In the first step, the surface of a flat plate structure with arbitrary rectangular holes is divided into several rectangular sub regions by an appropriate area-partitioned method, and the operational deflection shape(ODS) of each sub region is obtained by a continuous scanning at constant speed. Then, considering that the ODSs of all sub regions are spliced and the relative phases among them are different, the operational deflection shape of the whole structure is reconstructed based on linear function and other process. Finally, a plate structure with two arbitrary rectangular holes was taken as an example for modal test using the proposed method. At the same time, a validated experiment was performed using the SLDV measurement. The results show the mode shapes derived from the extended CSLDV are in agreement with those from SLDV and the Modal Assurance Criterion (MAC) between the two are all greater than 0.95. This method has great potential in practical engineering applications with the advantages of high efficiency and the full-field measurement.