RESEARCH ON THE IMPROVEMENT OF DIGITAL HOLOGRAPHIC PHOTO-ELASTIC METHOD

Through changing the polarization direction of reference light, the digital holographic photo-elastic method has been improved, which can measure two-dimensional stress field with high efficiency and accuracy. The principle of this method is introduced. Before and after loading, four couples of digital holographic images are obtained according to four polarization directions of reference light. With Fourier transform, filtering and inverse Fourier transform on the four couples of digital holographic images, four equations of light intensity can be obtained. By combining the stress-optics law, the value and directions of two principal stresses can be derived by solving the four equations. Compared with the traditional digital holographic photo-elastic method, the new method has the following advantages: no need to separate isochromatic and isoclinic curve; no need to determine the order of the fringes; no requirement for additional experimental devices or samples.