Application of Holographic Double Exposure Interferometry in the Displacement Measurement of a Cantilever Beam Based on Digital image Processing
Z.M. Zhao, L. Liu, Y.Y. Li, R.D. Ji, J.H. Zhang and L.B. Shen
The precise displacement measurement of cantilever beam could hardly be achieved because of the properties of cantilever beam such as flexibility, thinness and easy deformation. In the paper, the holographic double exposure interferometry is applied to record relative displacement field of the object under different load conditions, and therefore the interference fringe varies with the displacement of the object caused by different levels of load. A novel method of the fringe spacing measurement is introduced based on digital image processing. Meanwhile, the theoretical displacement distribution is calculated according to the numerical solutions of beams deflection curve. Numerical simulations are also carried out by finite element software ANSYS. The experimental results conform to the theoretical analysis completely; therefore, a new method to solve the problem of displacement measurement of cantilever beam is provided.
Keywords: Digital image processing, laser holographic interferometry, cantilever beam specimen, finite element (FE), fringe spacing