Research On Key Techniques Of Material Mechanical Properties Based On Digital Image Correlation Method

Digital image correlation(DIC) method has the advantages of full-field and non-contact measurement, which is widely used in machinery manufacturing, aerospace, materials and other fields. It is a powerful tool of the realization for real-time measurement of the deformation of the online materials under different environment. Mechanical properties measurement of high temperature materials under high temperature are very crucial to reliability evaluation, life prediction and security design of the spacecraft material and structure. Therefore, obtain accurate deformation and strain field information of high temperature material surface is the key and basic research on its mechanical property.In the thesis, the computer simulated speckle pattern was used to analyze and compare several classical integer pixel and sub-pixel correlation search method. Through theoretical derivation of the camera projection model, the camera was calibrated using the calibration board to obtain the distortion coefficient in the x, y direction and the conversion relationship between the pixel size and physical space. In high temperature measurement, in order to reduce the influence of surface radiation effect and the effect of noise and vibration, the paper presented an UV illumination DIC measurement method and an average gray method. Using the high temperature measurement system which was developed in this thesis, the effectiveness of these methods has been proved by the experiments data at high temperature of 1000℃ and the spectral analysis results.A set of DIC measurement software was developed based on Visual Studio 2010, and a DIC measurement system was developed to do actual measuring experiments which include rigid body displacement test, and the stress concentration test. The experimental results show that the DIC measurement system and software can achieve various measurement functions.