Helicopter structural elements and components fatigue resistance tests

Аuthors

Bokhoeva L. A.^1*, Kurokhtin V. Y.^1**, Perevalov A. V.^1***, Rogov V. E.^2****, Pokrovskii A. M.^3*****, Chermoshentseva A. S.^3******

1. East Siberia State University of Technology and Management, 40v, Klyuchevskaya str, Ulan-Ude, Republic of Buryatia, 670013, Russia
2. Baikal institute of nature management SB RAS, 6, Sakhiyanova str., Ulan-Ude, Republic of Buryatia, 670047, Russia
3. Bauman Moscow State Technical University, MSTU, 5, bldg. 1, 2-nd Baumanskaya str., Moscow, 105005, Russia

*e-mail: bohoeva@yandex.ru
**e-mail: kurokhtin91@gmail.com
***e-mail: alex_radio_8714@mail.ru
****e-mail: rogov54v@mail.ru
*****e-mail: ampokr@mail.ru
******e-mail: asch-13@ya.ru

Abstract

The paper considered fatigue resistance testing of helicopter structural elements on the example of helicopter rotor blades samples testing. Endurance testing of aircraft equipment components and structural elements consists in laboratory reproduction of external disturbances corresponding to the standard operating conditions, cyclic loading and functioning. However, these tests do not include studies related to the gradual damages accumulation leading to cracks initiation and propagation and finally to structural damage. In this regard, studying the process of cracks growth while full-scale tests of the samples presents special interest. The paper presents the brief description of blades full-scale tests process with concurrent video shooting. The samples are subjected to static loading, with subsequent additional bending load moment of variable sign. Video records of cracks growth were processed, and data on the crack subcritical growth time was obtained. This information is presented by the diagram, illustrating the crack growth time dependence of the crack growth rate. The paper analyzes measuring and test equipment used while testing for recording values of tensions occurring in the studied samples, due to bending load of variable sign applied to them. Fatigue resistance characteristics were determined, and fatigue graph was plotted. Arithmetic mean and root-mean-square deviation of endurance limit stress are obtained also.

Keywords:

lifetime tests, fatigue strength, probability chart, endurance limit, blade

References

1. Bokhoeva L.A., Rogov V.E., Kurokhtin V.Yu., Perevalov A.V., Chermoshentseva A.S. Sistemy. Metody. Tekhnologii, 2015, no. 4 (28), pp. 36-42.

2. Nebelov E.V., Pototskii M.V., Rodionov A.V., Gorskii A.N. Vestnik Moskovskogo aviatsionnogo instituta, 2016, vol. 23, no. 1, pp. 26-31.

3. Mokhov V.F. Trudy TsAGI, 1995, no. 2615, pp. 3-85.

4. Pivovarov V.A., Semenikhin R.L. Nauchnyi vestnik MGTU GA, 2012, no. 5 (179), pp. 107-113.

5. Ignatkin Yu.M., Konstantinov S.G. Trudy MAI, 2012, no. 57, available at: http://www.mai.ru/science/trudy/eng/published.php?ID=30875

6. Raschety i ispytaniya na prochnost' v mashinostroenii. Metody mekhanicheskikh ispytanii metallov. Metody ispytanii na ustalost'. GOST 25.502-79. (Calculations and strength tests mechanical engineering. Methods of metals mechanical testing. Fatigue testing methods. State Standard 25.502-79), Moscow, Standarty, 1986, 36 p.

7. Grishanina T.V., Kvak Ch. Vestnik Moskovskogo aviatsionnogo instituta, 2009, vol. 16, no. 5, pp. 296-299.

8. Bokhoeva L.A. Osobennosti rascheta na prochnost' elementov konstruktsii iz izotropnykh i kompozitsionnykh materialov s dopustimymi defektami (Peculiarities of calculating the strength of structural elements made of isotropic and composite materials with possible defects), Ulan-Ude, VSGUTU, 2007, 192 p.

9. Rudzei G.V. Trudy TsAGI, 1999, vol. 1, no. 2640, pp. 748-753.

10. Bokhoeva L.A., Perevalov A.V., Chermoshentseva A.S., Ergonov V.P., Rogov V.E. Vestnik VSGUTU, 2013, no. 6, pp. 31-35.

11. Bokhoeva L.A., Perevalov A.V., Chermoshentseva A.S., Kurokhtin V.Yu., Lygdenov B.D., Rogov V.E. Vestnik VSGUTU, 2013, no. 5, pp. 46-53.

12. Bokhoeva L.A., Pnev A.G. Izvestiya vysshikh uchebnykh zavedenii. Mashinostroenie, 2011, no. 5 (614), pp. 37-42.

13. Bokhoeva L.A., Pnev A.G. Mekhaniki XXI veku, 2011, no. 10, pp. 46-51.

14. Bokhoeva L.A., Kurokhtin V.Yu., Filippova K.A. Vestnik VSGUTU, 2015, no. 4, pp. 20-25.

15. Netfullov F.Kh., Ogorodov V.V., Shuvalov V.A., Dvoryankin A.V. Patent RU 2196313, 10.01.2003.

16. Gainutdinov V.G., Basinov M.E., Kasumov E.V., Shuvalov V.A. Poisk effektivnykh reshenii v protsesse sozdaniya i realizatsii nauchnykh razrabotok v rossiiskoi aviatsionnoi i raketno-kosmicheskoi promyshlennosti. Sbornik statei, Kazan, Kazanskii gosudarstvennyi tekhnicheskii universitet, 2014, pp. 13-16.

17. Obraztsov I.F. Stroitel'naya mekhanika letatel'nykh apparatov (Structural mechanics of aircrafts), Moscow, Mashinostroenie, 1986, 536 p.

18. Strizhius V.E. Nauchnyi vestnik MGTU GA, 2007, no. 9 (119), pp. 141-148.

19. Kogaev V.P., Makhutov N.A., Gusenkov A.P. Raschety detalei mashin i konstruktsii na prochnost' i dolgovechnost' (Machine parts and structures strength and durability Calculations), Moscow, Mashinostroenie, 1985, 223 p.