A STRUCTURAL VIBRATION MODAL TESTING METHOD BASED ON VISION SUBAREAS

To improve the accuracy of the vibration modal test by the vision method, a vision subarea that can estimate the field-of-view and the number of partitions for the subareas is proposed. The relationship between the measurement field-of-view parameters and the measurement accuracy is established considering the effects of low-resolution images and motion blur on the vibration measurement accuracy. The global field-of-view of the overall structure is partitioned to implement the vibration modal test. The frequency response function of the overall structure is obtained by combining the frequency domain data of the subareas, and the modal parameters of the structure are identified by the PolyMAX method. The validity of the proposed modal test method based on vision subareas is verified through the modal experiment of cantilever beams. The results show that the proposed approach can improve the signal-to-noise ratio of vibration response measurement and the identification accuracy of the modal parameters.