Research On Measuring Stress Field Using The Digital Holographic Photo-elastic Method Of Rotating Reference Light Polarization Plane

Photo-elasticity is an effective experimental way to solve stress analysis of engineering structures. With the development of photo-mechanics technology and digital holographic technology, the digital holographic photo-elastic method which combined photo-elastic method with digital holographic technology, becomes a hot topic.In traditional photo-elastic method, arithmetic line stripes, and line stripes, process lines stripes and isoclinic line stripes which indicate the stress distribution can be obtained. But the arithmetic line stripes and line stripes emerge at the same time, intermodulation, which results in difficulties on the stripes analysis, and is not easy to measure. Recently, there are double-model method, optical rotation, and reflective interferometry to separate the two sets of stripes. Two-model approach needs to produce two models with different materials and same size, and experiment under the same conditions, or the accuracy of the experiment will be affected; optical rotator is needed in optical rotation method, the complexity of the optical path and the adjustment difficulties increase the difficulty of the experiment, and error is great; reflective interferometry should coat reflective layer on model surface, optical path in complex, while arithmetic lines is easily deformed.. In addition, traditional holographic photo-elastic method needs continuous loading compensation method, rotating polarizer method to determine the series of various stripes, which is difficult to meet the requirement of practical applications. To avoid these shortcomings of traditional holographic photo-elastic method, the method of rotating reference light polarization plane is proposed by Li Juncang and Xu Wei.To prove the experimental feasibility of this theoretic method, research work of this paper have been done as follows:1. Based on the basic theory of rotating reference light polarization plane, actual experimental operation is done; according to practical situation, some requirements of theoretic method have been done flexible processing, such as obtaining enough object light, we added a new digital zoom system in the light path.2. The optical intensity images obtained by processing images using MATLAB which get by experiment. 3. Theoretical solution is done according to material mechanics and the information of model materials. Using the theoretical solution, we simulated the images of light intensity equations.4. In terms of comparative analysis of light intensity images obtained by experiments and theoretical solution simulation, we can see that light intensity images obtained by experiments and theoretical simulation are basically same. Initially proved the experiment feasibility of this method, and has further research value.