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  5. Methodological approach to confirmation of resource indicators when carrying out the state stand testing of helicopter main rotor blades

Methodological approach to confirmation of resource indicators when carrying out the state stand testing of helicopter main rotor blades

V. Dmytriiev, A. Serhiienko
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Description: The article is devoted to the optimization of time and material and technical costs when carrying out the state stand testing of helicopter main rotor blades. The analysis of the requirements of modern regulatory documents of the European Union Avia-tion Safety Agency, the European Defence Agency, as well as the safety standards for helicopters of 1961, the publication of the Central Aerohydrodynamic Institute, was performed. The required amount of testing to confirm the reliability of the design of the main rotor blade within a given resource was analyzed. In order to reduce the costs and time for testing, it was proposed not to determine the actual fatigue characteristics of the blades when conducting the state stand testing of main rotor blades. To con-firm the specified life of the blades, it was proposed to carry out tests at operational loads, increased by 20%, with a margin of loading cycles equal to three. When forming a typical loading cycle for the main rotor blades, it is necessary to take into consid-eration the tactics of the use of army aviation, taking into account the new combat experience gained during the anti-terrorist operation. Such an approach to confirming a resource does not contradict regulatory documents, and the possible risks of incor-rect assessment of a resource, according to mathematical statistics, do not exceed the risks assumed by more material-intensive methods. The selected approach will require 3 samples of the blade for life tests, which will be divided into butt and center parts, while at least 12 samples of the blade would be required to determine the actual fatigue characteristics. In the article, it was proposed to use a resonant test bench for carrying out life tests, on which it is possible to implement loading with a frequency up to 20 Hz, which will significantly speed up testing compared to tests on a three-component test bench where a loading frequency of 1-2 Hz is realized. In addition, in order to speedily reach the blades to the troops, a step-by-step increase of the resource from the initial 300 hours to the specified 1200 hours was proposed.


Keywords: the state stand testing, helicopter main rotor blades, resource.

References

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Reference:
 Dmytriiev, V.A. and Serhiienko, A.I. (2019), “Metodychnyi pidkhid do pidtverdzhennia zadanykh resursnykh pokaznykiv pry provedenni derzhavnykh stendovykh vyprobuvan lopatei nesuchoho hvynta vertolotu” [Methodological approach to confirmation of resource indicators when carrying out the state stand testing of helicopter main rotor blades], Systems of Arms and Military Equipment, No. 2(58), pp. 86-91. https://doi.org/10.30748/soivt.2019.58.11.