Artykuły (WM)

Stały URI dla kolekcjihttp://hdl.handle.net/11652/206

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2007 - 200912010 - 20151

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Autorsearch.filters.applied.operator.equals: search.filters.author.Olejnik, PawełMa przypisane plikisearch.filters.applied.operator.equals: Tak

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Teraz wyświetlane 1 - 2 z 2
  • Pozycja
    Identification of a non-linear damping coefficient characteristics in the free decay test of a single pendulum with friction.
    (Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Awrejcewicz, Jan; Olejnik, Paweł
    A pendulum in form of an equal arms angle body being a part of a two degrees-of-freedom mechanical system with friction is identified with respect to the observed in uence of some resistance of its rotational motion in ball bearings. It is damped in a much more complex manner, what could be considered as a non-linear damping. There is supposed between others, that the effective non-linear damping characteristics depends on a few effects such as fluid friction caused by vibrations of the pendulum with two springs in the air, as well as unknown kinds of a frictional resistance existing in ball bearings. The model under investigation finds its real realization on a laboratory rig designed for experimental investigations of viscous and structural frictional effects. A transient response oscillations of the pendulum are described by the explicitly state-dependent free decay. A free decay test of the pendulum with the state dependent non-linear parameters of damping and stiffness has been performed in this paper. It provided interesting observations that led to elaboration of a method of the overall damping coefficient identification. Effects of application of the proposed semi-empirical method of identification of the overall damping and stiffness coefficients have been illustrated and discussed.
  • Pozycja
    Occurrence of strick-slip phenomenon.
    (Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2007) Awrejcewicz, Jan; Olejnik, Paweł
    A self-excited system wit h unilateral friction contact modelled by a two degrees-of-freedom mechanical system, where the normaI farce varies during displacement of a block has been studied. The constructed real laboratory rig approximates the investigated system, and it includes feedback reinforcement of the friction force acting on the vibrated block. Some methods of data acquisition and data handling procedures are proposed for experimentally observed results and data collection. A novel static friction force model for both positive and negative velocities of the base is proposed.