Four ways to determine modes of variation in a plate

Four methods for detecting vibration modes are evaluated. Holographic interferometry, vibravision, impact modal testing, and FEM calculations are utilized to estimate the vibration modes of a 202 x 175 mm steel plate. The experimental configuration and apparatuses for each optical procedure and the model for the FEM calculations are described. The operation of each method and their advantages and disadvantages are compared. The data reveal that the holographic interferometry, and vibravision procedures provide accurate data on mode shapes and out-of-plane amplitudes of vibration for every point on the plate, the impact model testing procedure provide only accurate resonance frequencies, and the FEM methods supplies accurate vibration data; however, it requires extensive mathematical knowledge. It is noted that the four methods are all effective and should be applied in combination.