Інженерна механіка та транспорт
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Item Дослідження демпфера нормально закритого чи відкритого з керуванням по тиску стиснутого повітря пневматичного привода(Видавництво Львівської політехніки, 2013) Ковриженко, Д. В.A mathematical model of the pneumatic actuator with the damping rod at the end of stroke was made. Transient movement of the actuator piston is considered as adiabatic and in pseudo steady-statement. It is assumed that the compressed air is an ideal gas. Not any air leak in the drive is out. Designs of regulators normally open and closed adaptive to the level of pressure in the chambers of the drive was create. The design of the damper to the universal changeover from normally open to normally closed and vice versa. A mathematical model of adaptive dampers for the influence of design parameters on the process of damping was written. The greatest impact parameters are: the diameter of the piston, the spring constant, the zero offset spring, and the angle forming the rod to its axis. The optimal design of the drive, which provides a smooth stop for a range of pressure as the nominal flow rate, mass, and the constant force load, was found. In work showed the efficiency of a damper on the parameters established speed braking and a swing speed.Item Вплив пружного закріплення лопатей на динаміку вітроколеса(Видавництво Львівської політехніки, 2011) Корендій, ВіталійЗ метою встановлення впливу параметрів жорсткості лопатей на їх динамічну поведінку при складному обертанні вітроколеса поставлено задачу про коливання жорсткої лопаті, пружно приєднаної одним кінцем до жорсткого диска, що зв’язаний з жорстким валом. Для побудови нелінійних рівнянь руху пружно закріпленої жорсткої лопаті при складному обертанні вітроколеса застосовано теорему Коріоліса та принцип Даламбера. Отримано частинний розв’язок рівнянь руху, що описує режим сталих коливань жорсткої лопаті. Встановлено, що система має малу структурну жорсткість, а резонансні режими у ній не виникають. The solution of the actual problem that consists in investigation of typical vibration processes in compound rotation of rigid blades, elastically attached to the wind wheel, is given in this article. With the aim to establish the influence of stiffness parameters of rigid blades on their dynamic behavior in compound rotation of the wind wheel, the problem about vibrations of rigid blades, attached by one end to the rigid disc connected with a rigid shaft, is set up. The theorem of Coriolis and the principle of Dalamber are used for construction nonlinear equations of motion of rigid blade in compound rotation of the wind wheel. Analytical expressions for calculation the vectors of transposed (2), comparative (5), coriolis (6) and full (1) acceleration of the element of the blade are deduced. These expressions enable us to compute the components of inertial loads on the element of the blade, which are caused by rotation of the shaft of the wind wheel. We eliminate the system of nonlinear equations (7) of motion of rigid blade to one linear differential equation of vibration (8) using some assumptions described in the article. The partial solution (9) of received equation that describes behavior of constant vibrations of rigid blade is found. Mathematical and computer modeling of dynamics of described system is realized. We take into consideration the possibility of variation of some typical parameters, such as angular velocity of rotation or turning of the wind wheel, number of blades, geometric dimensions and density parameters of the blade etc. Some graphical results of computer modeling (graphics of the oscillation amplitude) are given in the article. We prove that resonance processes on the elementary areas of blades in case of compound rotation of the wind wheel with rigid blades elastically attached to the rotor don’t take place and the system has small structural stiffness.