Research And Application Of Synchrotron Radiation Computed Tomography Technique

In this paper, the principle for SR-CT technique, its study and application at present are firstly reviewed. Based on previous works, the technique of SR-CT is investigated in detail. In order to improve the contrast of reconstruction images for the materials which their elements absorbance index are very close, the technique of diffraction enhanced SR-CT is developed. To acquire the 3-D displacement field of inner structures for objects, the 3-D digital image correlation method is researched. At last, the technique of SR-CT is applied to investigate the mechanical properties of aluminum foamed under quasi-static compression.The main research topics and creative points are concluded as follows:1. Arithmetic for SR-CT technique are studied and some parameters in arithmetic are optimized. A new method named mix-arithmetic is given. The reconstruction images quality of incomplete projection data for SR-CT technique is analyzed and the relationship between the quality and the absent amount of projection data is obtained. The methods to improve the quality of reconstruction images for incomplete projection data are given. The error mechanism of SR-CT technique is analyzed and four basic error forms are presented.2. The technique of diffraction-enhanced SR-CT is developed. For the material in which their elements absorbance indexes are very close, can't clearly be resolved by the absorption imaging technique. The technique of diffraction-enhanced imaging is studied. Furthermore, it is combined with the SR-CT technique to improve the contrast of reconstruction images for such materials. Experimental results confirm this new technique.3. Based on the reconstruction images obtained by SR-CT technique, 3-D digital image correlation method is developed to acquire the 3-D displacement field of inner structures. The 3-D searching window, correlative function, the fitted function of correlation coefficient and the process of calculating are given. The numerical simulation results confirm this method.