Evaluation of the aircraft vibration characteristics using high-torque statistic in the case of limited experiments

Аuthors

Maslov G. A.^1*, Mitenkov V. B.²

1. PJSC Yakovlev , 68, Leningradskiy prospect, Moscow, 125315, Russia
2. Flight Research Institute, 2A, Garnaeva str., Zhukovsky, Moscow region, 140182, Russia

*e-mail: georgiymaslov@gmail.com

Abstract

During the flight in the process of separation of aircraft moving mass as a rule the high dynamic loads appear on the aircraft, its equipment and construction elements of small systems on board. As an avionics on aircraft board can be instrumentation equipment, control systems and small-sized engines. As a result of the flight and ground experiments the question of received data processing with unconventional ways arises. In this paper the construction of empirical laws of vibration loads distribution is proposed by using high-torque statistics.
It is shown that the considered spectral array of samples shares into vertical columns «tied» to a fixed frequency range or to the narrow intervals around these frequencies, for example, to the 1/3-octave frequency bands. In each vertical columns of described spectral model the spectral vibration statistic is formed from sample spectrum of certain amount that qualifies as a random variable.
In this paper it is proposed to estimate the experimental results and the law of distribution in terms of asymmetry and excess. A distinctive feature of the presented solution for moments order more than two is that this approach for dealing with the empirical distribution provides much better rate of convergence in comparison with the similar solutions using low-torque vibration statistic when the moments order in less or equal to two.
The paper presents a table representation of both solutions. The result is a generalization of the probabilistic model of random vibration loads spectral characteristics for certification assessment of the vibration environment on the aircraft.
In conclusion we can draw the following statements: from the available data with the use of high-torque statistics it is possible to obtain distribution law characteristics enabling widespread in current processes evaluating.

Keywords:

random vibration, high-torque statistic, low-torque statistic, spectral characteristics

References

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