Determining limiting amplitude of hardened parts cycle with stress concentrators with compressing average stresses

DOI: 10.34759/trd-2020-114-08

Аuthors

Shlyapnikov P. A.

Samara National Research University named after Academician S.P. Korolev, 34, Moskovskoye shosse, Samara, 443086, Russia

e-mail: pawel777000@yandex.ru

Abstract

The purpose of this work consists in developing a technique for the limiting amplitude quantifying of hardened samples with stress concentrators at various compressive average cycle stresses.

To confirm the previously obtained theoretical solution on predicting the maximum amplitude of parts with stress concentrators, hardened by the surface plastic deformation (PPD) methods at the central tension-compression cycle asymmetry and compressive average stresses of the cycle, an experimental study of cylindrical samples made of 45 steel with semicircular profile incisions hardened by pneumatic blasting was performed.

Both non-hardened and hardened cylindrical samples with concentrators applied to them in the form of an annular incision of a semicircular profile were subjected to studying. Incisions were being applied on the hardened sample after pneumatic blasting of a smooth cylindrical sample. As the result, the increment of the maximum amplitude of samples with stress concentrators due to surface hardening, as well as the redistribution of residual stresses of a hardened smooth sample as a result of applying the concentrator to the hardened surface of the sample were being determined.

Experimental limit amplitude determining of non-strengthened and hardened samples was performed with the UMM-01 testing machine, allowing implementing both tensile and compressive average cycle stresses. The results of the endurance limit determining are summarized in a table. For comparison, the table shows the calculated data obtained earlier by the computer modeling.

The author proposes to perform estimation of the hardened samples and parts with different asymmetry degree by the cycle limiting amplitudes diagrams with account for residual stresses. The limiting amplitudes diagram is based the modified Gann diagram.

A limiting amplitudes diagram of a cycle with average compressive stresses was obtained for an asymmetric cycle, where a hardened sample with a concentrator and a non-hardened sample with a stress concentrator were employed.

Fr om geometrical considerations, the equation for the coefficient of of residual stresses effect on the limiting amplitude at various compressive stresses of the stretch-compression cycle was obtained. As the result, a technique for the limit amplitude of hardened samples and parts estimating employing the lim it amplitudes diagram of the stress cycle of parts, with account for residual stresses was proposed. A simple equation for calculating maximum amplitude of hardened parts with concentrators at different degrees of cycle asymmetry was proposed. The obtained scientific results can be used in strength calculations without lengthy and costly tests.

Keywords:

residual stresses, stresses concentration, compressive average stresses, limiting amplitudes diagram, cycle asymmetry, fatigue resistance

References

1. Meshkov Yu.А., Shiyan A.V. Meshkov Yu.A., Shiyan A.V. Mekhanika mashin, mekhanizmov i materialov, 2015, no. 3, pp. 59 – 63.

2. Nikitin I.S., Burago N.G., Nikitin A.D., Yakushev V.L. Vestnik Permskogo natsional’nogo issledovatel’skogo politekhnicheskogo universiteta. Mekhanika, 2017, no. 4, pp. 238 – 252.

3. Dobrovol’skii D.S. Zavodskaya laboratoriya. Diagnostika materialov, 2016, vol. 82, no. 9, pp. 65 – 69.

4. Kostichev V.E. Vestnik Samarskogo gosudarstvennogo aerokosmicheskogo universiteta imeni akademika S. P. Koroleva (natsional’nogo issledovatel’skogo universiteta), 2015, no. 1 (14), Ch. 1, pp. 147 – 153.

5. Firsanov V.V., Vo A.Kh., Chan N.D. Trudy MAI, 2019, no. 104. URL: http://trudymai.ru/eng/published.php?ID=102130

6. Shakirtov M.M. Trudy MAI, 2016, no. 89. URL: http://trudymai.ru/eng/published.php?ID=72589

7. Vakulyuk V.S., Shadrin V.K., Lunin V.V., Kiselev P.E., Shlyapnikov P.A. Nauchno-tekhnicheskii vestnik Povolzh’ya, 2015, no. 6, pp. 108 – 111.

8. Korovaitseva E.A. Trudy MAI, 2020, no. 110. URL: http://trudymai.ru/published.php?ID=112827. DOI: 10.34759/trd-2020-110-10

9. Polonik E.N., Surenskii E.A., Fedotov A.A. Trudy MAI, 2017, no. 92. URL: http://trudymai.ru/eng/published.php?ID=76755

10. Yashkova S.S. Molodoi uchenyi, 2017, no. 1, pp. 99 – 101.

11. Zoan K.Kh., Firsanov V.V. Trudy MAI, 2020, no. 110. URL: http://trudymai.ru/published.php?ID=112851. DOI: 10.34759/trd-2020-110-10

12. Yudin D.A., Firsanov V.V. Trudy MAI, 2020, no. 112. URL: http://trudymai.ru/published.php?ID=116343. DOI: 10.34759/trd-2020-112-8

13. Andryukova E.A. Metallurgiya. Ostatochnye napryazheniya v metalloproduktsii (Metallurgy. Residual stresses in metal products. Study guide for universities), Moscow, Iz-vo Yurait, 2018, 247 p.

14. Pkhon Kh.K., Sysoev E.O., Kuznetsov E.A., Min K.Kh. Trudy MAI, 2019, no. 108. URL: http://trudymai.ru/published.php?ID=109237 . DOI: 10.34759/trd-2019-108-2

15. Trunin A.V. Povyshenie effektivnosti tekhnologii uprochneniya valov poverkhnostnym plasticheskim deformirovaniem putem sozdaniya v nikh zadannoi sistemy ostatochnykh napryazhenii (Efficiency improving of shaft hardening technology by surface plastic deformation by creating a specified system of residual stresses in them). Abstract of doctor’s thesis, Moscow, 2015, 19 p.

16. Lesota A.V., Rubanik V.V., Rubanik V.V. Aktual’nye problemy prochnosti (Up-to-date problems of strength), Vitebsk, Vitebskii gosudarstvennyi tekhnologicheskii universitet, 2018, pp. 373 – 384.

17. Bagmutov V.P., Vodop’yanov V.I., Kondrat’ev O.V., Badikov K.A. Izvestiya Volgogradskogo gosudarstvennogo tekhnicheskogo universiteta, 2015, no. 5 (160), pp. 69 – 73.

18. Kirpichev V.A., Kostichev V.E., Shlyapnikov P.A. Problemy mashinostroeniya i avtomatizatsii, 2020, no. 1, pp. 136 – 140.

19. Ivanov S.I., Pavlov V.F., Minin B.V., Kirpichev V.A., Kocherov E.P., Golovkin V.V. Ostatochnye napryazheniya i soprotivlenie ustalosti vysokoprochnykh rez’bovykh detalei (Residual stresses and fatigue resistance of high-strength threaded parts), Samara, Izd-vo SamNTs RAN, 2015, 170 p.

20. Kirpichev V.A., Filatov A.P., Mikhalkina S.A., Shlyapnikov P.A. Trudy desyatoi Vserossiiskoi nauchnoi konferentsii s mezhdunarodnym uchastiem “Matematicheskoe modelirovanie i kraevye zadachi”: sbornik trudov, Samara: Samarskii gosudarstvennyi tekhnicheskii universitet, 2016, vol. 1, pp. 113 – 115.

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