OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 7 No. 3 2025 dependencies with approximation reliability levels of R² = 0.949 for the Young’s modulus dependency curve and R² = 0.993 for the Poisson’s ratio dependency curve. This indicates a strong correlation between the values of ν, E and the grain size factor. 2 0 0054 0 054 0 3 . . . x x ν = ⋅ − ⋅ + ; 2 1 75 12 25 62 35 . . . E x x = ⋅ − ⋅ + . It should be noted that the obtained regression relations are not claimed to be universal and can only be applied under the conditions in which they were derived. For instance, the values of ν and E can be determined for a grinding wheel with the following characteristics: an abrasive of white electrocorundum with a hardness grade of L and an average structure number of 6 on a ceramic bond. For a grinding wheel with a grit size of F100 (grit size ranging from 0.15 to 0.11 mm), the values of Poisson’s ratio and Young’s modulus are 0.164 and 42.66 GPa, respectively. Similarly, the effect of hardness on the elastic performance of grinding wheels has been established. An increase in grinding wheel hardness results in higher values of Young’s modulus. Young’s modulus characterizes the stiffness of the system and its ability to resist elastic deformation. This is reflected in the study of natural vibrations of a solid body. Grinding wheels with higher E values exhibit a shift of natural frequencies toward the high-frequency range (see Fig. 5). The change in hardness of grinding wheels with the same structure is due to the redistribution of the proportions of the main components: grain, bond, and pores. An increase in hardness is promoted by a decrease in pore volume and an increase in bond volume. Therefore, it can be concluded that there is a positive correlation between hardness and stiffness, or between the characteristics of plastic and elastic deformation of the grinding wheel, as expressed by Young’s modulus. Poisson’s ratio increases with hardness in the interval from L to P. After reaching a maximum value of 0.23, it begins to decrease. See fig. 7 for the graphs. The obtained regression dependencies have approximation confidence levels close to unity (R² = 0.9913 for the Young’s modulus curve and R² = 0.999 for the Poisson’s ratio curve). Therefore, there is a strong correlation between the values of ν, E, and the hardness factor. 2 0 0162 0 0877 0 109 . . . x x ν = − ⋅ + ⋅ + ; 2 1 75 0 35 40 5 . . . E x x = ⋅ − ⋅ + . These empirical regression models can be used to determine the values of ν and E for white electrocorundum grinding wheels with an F60 grain size and medium structure on a ceramic bond for several hardness grades: K, M, O, R, and T: – 25A F60 K has values ν = 0.148; E = 40.76 GPa; – 25A F60 M has values ν = 0.200; E = 43.91 GPa; Fig. 6. Influence of grinding wheel grit on the value of Poisson’s ratio and Young’s modulus
RkJQdWJsaXNoZXIy MTk0ODM1