ЭКСПЕРИМЕНТАЛЬНОЕ ИССЛЕДОВАНИЕ ВЫНУЖДЕННЫХ КОЛЕБАНИЙ САМОЛЕТА ПРИ ОТРЫВЕ ЛОПАТКИ ДВИГАТЕЛЯ

摘要

The presented article is a generalization of works relating to the ground reproduction of the force impacts on the aircraft structure, on the part of the engine with imbalance in case of the blade loss. While ground testing the engine rotor does not rotate, and rotating force is formed by the fixedly installed vibration exciters. The immediate purpose of the experiment consists in frequency characteristics measuring, which associate the aircraft vibrations with the excitation force from the engine rotor imbalance. These characteristics are necessary for the computational dynamic scheme correction of the structure employed in loads computing in flight, possibly prolonged, while the blade break-away over the water surface. These computations are used for the aircraft safety evaluation while the blade loss. The article presents the testing technique and facilities. The estimates of the modelling method applicability and its trustworthiness are given for the first time. The text is supplemented by the examples of real data of the tests. The quantitative confirmation for the case of the ground experiment is given in the applicability esteems of the rotating inertial force reproduction by the harmonic forces stationary in space. At the same time, it was noted that the loads calculation while flight fluctuations, with a high level of the engine overloading, can not be based on either use of only relative acceleration of the blade, or the approximate theory of the gyroscope. The circumstance of the experiment performing while the compulsory routine tests prior to its first flight was considered separately as practically the only possible for the experiment under consideration. The domestic tests on the aircraft with the engine blade loss modelling performed for the first time revealed the feasibility and possibility of their realization in conditions of dire time deficit prior to the first flight. The presented details and features of the technique allow apply them in the future in the practice of such tests by the design bureau itself. The main result is substantiation and practical confirmation of the possibility of reproducing on the ground the forced oscillations of an airplane after the blade loss, and while the mandatory regular modal tests.%Приведены: методика наземных испытаний с моделированием сил при невращающемся роторе двигателя, основные соотношения и границы их применения, данные о средствах воспроизведения силовых воздействий на самолет, оценки достоверности и примеры результатов эксперимента с измерением частотных характеристик в режиме авторотации.