Research Of Uneven Density Field Modeling And Arithmetic Of CT Computer Simulation And Projection

Fatigue is the main form of damage of the engineering components under cycle loading, and it is also the big threat in some engineering filed such as aerospace. Inspecting the health state of the engineering components, which is still under the fatigue life, become a valuable researching topic for guaranteeing the safety and reliability of the key components of aircrafts, watercrafts and engines in use. Technique of ICT is a complex technique related to radiology, optics, electronics and computer. Industrial computed tomography (ICT) is mainly used in the field of non-destructive testing (NDT) of part and non-destructive evaluation of part. It is regarded as the best method of non-destructive testing in the world. Now, the great progress in technique has provide some advanced non-destructive evaluation methods and theory model for pre-estimating the fatigue life, and made it possible to use ICT to inspect non-destructively and visually the fatigue crack groups initiation and propagation in the engineering components which is in use or under loading experience conditions and to analyze quantitatively the uneven density filed caused by the fatigue crack groups.This paper's aim is to provide, through the simulation way, the projective images which can be used to analyze the micro fatigue crack group damage, and to shorten the research time and reduce the experience cost greatly. Under deeply knowing the ICT technique and it's simulation methods, the paper discuss the modeling methods of the CT simulation model phantom based on the VOXEL model, the intersection and projection algorithm of this new model phantom used in the ICT simulation system, and finish the computer simulation of micro crack group initiation and propagation with this new phantom in 3-D space according the real rules of this process. Another point of this paper is to study the method of direct modeling and indirect modeling of uneven density field in VOXEL model phantom. In the end, it introduce the partially subdivision method to setup some sub-VOXEL model, which can reflect the density field change cause by the micro crack group, in some voxel cubes of the VOXEL model phantom, and presents the digital material model phantom which was composed by the VOXEL model file and sub-VOXEL model files together. There is an uneven density field cause by the micro crack group in the digital material model phantom.