539.4

Strength, macrostress theory, crack propagation resistance in the material (Κ_1с), macrostress concentration coefficient Κm, average technical strength of the material (σ_в), Poisson's ratio (ν), structural parameter (ρ) and crack (defect) length (2l).

In modern conditions, when improving methods for calculating real structure materials and products made of them, it is necessary to take into account their physical and mechanical properties and microstructure as more adequately and thoroughly as possible. All physical materials are characterized by a certain structural heterogeneity (defects and irregularities in the crystal lattice, microcracks, pores, microinclusions, scratches, marks, etc.) The microinhomogeneity of the material structure can be accounted for by a simple and quite effective theory of M. Y. Leonov and K. M. Rusynko [1–3]. According to this theory, a body is called macrohomogeneous in a certain area if mechanical properties of any elementary volume conditionally cut out of the specified area are the same. According to this model, a solid is considered as a continuous medium, around each point of which a minimum volume V₀ can be identified that still has (based on statistical data) mechanical properties determined in conventional studies of macro-bodies. For this volume V₀, a sphere of radius ρ is chosen, which is taken as a structural parameter of the material. The paper presents a simplified method for determining the structural parameter ρ for a number of structural materials.

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2. Leonov M. Ya., Rusynko K. M. Do makroekonomichnoi teorii krykhkoho ruinuvannia. Dop. AN URSR. 1961. No. 12. P. 1582–1586.
3. Leonov M. Ya., Rusynko K. M. Makronapriazhenyia upruhoho tela. Prykl. Mat. y tekhn. fyz. 1963. No. 1. P. 104–110.
4. Panasiuk V. V., Berezhnytskyi L. T., Hromiak R. S. O vlyianyy struktury materyala na rasprostranenye treshchyn v protsesse rastiazhenyia tela. Dokl. AN USSR. 1976. Ser. A. No. 9. P. 811–816.
5. Panasiuk V. V., Berezhnytskyi L. T., Hromiak R. S. O vlyianyy struktury materyala na rasprostranenye treshchyn v protsesse szhatyia tela. Dokl. AN USSR. 1976. Ser. A. No. 10. P. 919–924.
6. Panasiuk V. V., Berezhnytskyi L. T., Hromiak R. S. O vlyianyy struktury materyala na rasprostranenye treshchyn  vozle ostrokonechnykh vkliuchenyi. Dokl. AN USSR. 1976. Ser. A. No. 12. P. 1096–1101.
7. Berezhnytskyi L. T., Ratych L. V., Hromiak R. S. Sviaz lokalnoho razrushenyia vblyzy treshchyn so strukturoi. Tezysy dokladov Vsesoiuznoi nauchno-tekhnycheskoi konferentsyy “Struktura y prochnost staly y splavov” Kyev, 1976. P. 41–43.
8. Ratych L. V. Ob opredelenyy ϶fektyvnykh ko϶fytsyentov kontsentratsyy. 1965. 1. No. 3. P. 317–325.
9. Iarema S. Ya., Ratych L. V. Vlyianye mykroneodnorodnostei struktury materyala na prochnost polos s hyppebolycheskymy vyrezamy. Fyz.-khym. mekhanyka materyalov. 1965. 1. No. 3. P. 317–325.
10. Hromiak R. S. K voprosu o nachalnom napravlenyy rasprostranenyia treshchyn. V sb.: materyaly Ⅶ konferentsyy molodykh uchenykh FMY AN USSR. Sektsyia FKhMM. Lvov, 1975, Sbornyk deponyrovan v VYNYTY №1138-76 Dep ot 9 aprelia 1976 h. P. 36–38.
11. Hromiak R. S. Dyahrammy predeloho ravnovesyia dlia mykroneodnorodnykh khrupkykh tel. Fyz.-khym. mekhanyka materyalov. 1977. 13. No. 1. P. 121–122.
12. Stashchuk M., Nytrebych Z., Hromiak R. Otsiniuvannia teoretychnoi mitsnosti porystykh materialiv za teoriieiu katastrof. Visnyk TNTU. No. 3 (99). 2020. P. 44–54.
13. Oleinyk N. V., Nho Van Kuet. Opredelenye viazkosty razrushenyia materyalov po ykh mekhanycheskym svoistvam. Probl. prochnosty. 1976. No. 1. P. 72–77.
14. Cherepanov H. P. Mekhanyka khrupkoho razrushenyia. M.: Nauka, 1974. 640 p.

1. Leonov M. Ya. Osnovу mekhanyky upruhoho tela. Frunze: Yzd. AN Kyrh. SSR, 1963. 328 р.
2. Leonov M. Ya., Rusynko K. M. Do makroekonomichnoi teorii krykhkoho ruinuvannia. Dop. AN URSR. 1961. No. 12. P. 1582–1586.
3. Leonov M. Ya., Rusynko K. M. Makronapriazhenyia upruhoho tela. Prykl. Mat. y tekhn. fyz. 1963. No. 1. P. 104–110.
4. Panasiuk V. V., Berezhnytskyi L. T., Hromiak R. S. O vlyianyy struktury materyala na rasprostranenye treshchyn v protsesse rastiazhenyia tela. Dokl. AN USSR. 1976. Ser. A. No. 9. P. 811–816.
5. Panasiuk V. V., Berezhnytskyi L. T., Hromiak R. S. O vlyianyy struktury materyala na rasprostranenye treshchyn v protsesse szhatyia tela. Dokl. AN USSR. 1976. Ser. A. No. 10. P. 919–924.
6. Panasiuk V. V., Berezhnytskyi L. T., Hromiak R. S. O vlyianyy struktury materyala na rasprostranenye treshchyn  vozle ostrokonechnykh vkliuchenyi. Dokl. AN USSR. 1976. Ser. A. No. 12. P. 1096–1101.
7. Berezhnytskyi L. T., Ratych L. V., Hromiak R. S. Sviaz lokalnoho razrushenyia vblyzy treshchyn so strukturoi. Tezysy dokladov Vsesoiuznoi nauchno-tekhnycheskoi konferentsyy “Struktura y prochnost staly y splavov” Kyev, 1976. P. 41–43.
8. Ratych L. V. Ob opredelenyy ϶fektyvnykh ko϶fytsyentov kontsentratsyy. 1965. 1. No. 3. P. 317–325.
9. Iarema S. Ya., Ratych L. V. Vlyianye mykroneodnorodnostei struktury materyala na prochnost polos s hyppebolycheskymy vyrezamy. Fyz.-khym. mekhanyka materyalov. 1965. 1. No. 3. P. 317–325.
10. Hromiak R. S. K voprosu o nachalnom napravlenyy rasprostranenyia treshchyn. V sb.: materyaly Ⅶ konferentsyy molodykh uchenykh FMY AN USSR. Sektsyia FKhMM. Lvov, 1975, Sbornyk deponyrovan v VYNYTY №1138-76 Dep ot 9 aprelia 1976 h. P. 36–38.
11. Hromiak R. S. Dyahrammy predeloho ravnovesyia dlia mykroneodnorodnykh khrupkykh tel. Fyz.-khym. mekhanyka materyalov. 1977. 13. No. 1. P. 121–122.
12. Stashchuk M., Nytrebych Z., Hromiak R. Otsiniuvannia teoretychnoi mitsnosti porystykh materialiv za teoriieiu katastrof. Visnyk TNTU. No. 3 (99). 2020. P. 44–54.
13. Oleinyk N. V., Nho Van Kuet. Opredelenye viazkosty razrushenyia materyalov po ykh mekhanycheskym svoistvam. Probl. prochnosty. 1976. No. 1. P. 72–77.
14. Cherepanov H. P. Mekhanyka khrupkoho razrushenyia. M.: Nauka, 1974. 640 p.