Technique for obtaining an integral characteristic of the structure of a loaded composite material based on microtomographic research data

Abstract

Composite materials are characterized by an uneven distribution of the density value in the volume. Under mechanical loading, the parameters of the density distribution over the volume change, which leads to qualitative changes in the structure up to the formation of discontinuities, and the shock-wave sensitivity also changes accordingly. The exact distribution of regions with different density values in the bulk of the material is established by means of X-ray microtomography.The purpose of the work was to develop a technique for obtaining an integral characteristic of the structure of a loaded composite material based on microtomographic examination data. Samples of a carbon composite material in the initial state and subjected to loading with various degrees of deformation were used as objects of study. Synchrotron radiation from a VEPP-3 charged particle accelerator (Institute of Nuclear Physics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia) was used as an X-ray source for microtomographic studies.To extract the indicated integral characteristic of the structure from the density matrices of the material, an image analysis technique was developed based on sequential image filtering in order to select regions with a given range of gray shades from the total matrix. To decompose the general matrix into derivatives and their subsequent analysis, the universal software ImageJ-FiJi was used.Based on the processing results, a dependence was obtained that characterizes the ratio of the size of the local region of the structure with a characteristic density value to the distance between these regions, that is, the desired integral characteristic from the conditional density range of the analyzed regions.