Micro-displacement, Stain and Stress Measurement Based on Electronic Speckle Pattern Interferometry

A micro-displacement, strain and stress measurement method based on electronic speckle pattern interferometry (ESPI) technique is proposed, and the measuring device is designed. Two symmetric laser beams are illuminated on the optical rough surface of a steel cantilever beam, and then speckle images are photographed by CCD. A series of filtering processing is carried out for subtracted images and FEM analysis is performed. Using the speckle fringe patterns finally achieved, displacement, strain and stress can be calculated. By comparing displacement, strain and stress measured by this method with simulation results, feasibility and engineering application value of this method have been proved.