PSI - Issue 41

A.M. Ignatova et al. / Procedia Structural Integrity 41 (2022) 550–556 6 Ignatova A.M., Balakhnin A.N., Bannikov M.V., Kuper K.E., Nikitiuk A.S., Naimark O.B./ Structural Integrity Procedia 00 (2019) 000–000 555

For the first and second samples, i.e., the unloaded sample and the sample loaded in the stress raiser zone, it is typical that a significant part of the defects occurs in the group with the dispersion factor value of 1.9-2.2. For the loaded sample located along the loading axis during the test, it is typical that the most extensive group is the pores with a dispersion factor value of 0.79-0.91. The distance between the defects is the most varied in the sample before loading and the least varied in the loaded sample located in the stress raiser zone. The position of points in Fig. 5 is a visual representation of the fact that different deformation conditions result in different pictures of the distribution of porosity elements in the coordinates “distance between porosity elements – morphometric parameters of porosity.” Deformation in the stress raiser zone mostly leads to the reduction in the distances between the porosity elements, whereas the deformation outside of the stress raiser zone mostly provides for the dimensional evolution of porosity elements. It is worth mentioning that the dispersion factor of porosity elements in the loaded samples tends to be generally lower than in the unloaded sample; this confirms the assumption that there is an overall trend toward the dimensional evolution of defects in CCCM, its rate depending on the uniformity of stress distribution in the material during deformation. Taken together, the presented data provide for a qualitative and quantitative assessment of the porosity elements in the macrostructure of composite material at different loading conditions, both among themselves and relative to the state of the material before loading. Conclusions. Thus, a method has been proposed to obtain an integral characteristic of a structure of a loaded composite material based on the data of a microtomographic examination, representing the distributions of elements of the structure with various densities in the coordinates “distance between elements with known density – morphometric parameters of elements.” Funding . This research was supported by the Russian Science Foundation (grant no. 21-79-30041). References Murashov V.V. Nondestructive control of blanks and parts from carbon-carbon composite material for reusable spacecraft Buran // Proceedings of VIAM. 2013. No. 4. (electronic scientific journal). 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