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Sirvi Autor "Cerpinska, M." järgi

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  • Pisipilt
    Kirje
    Study of simultaneous collisions in agricultural machinery and technology
    (Estonian University of Life Sciences, 2025) Sokolova, S.; Beresnevich, V.; Viba, J.; Irbe, M.; Cerpinska, M.
    The paper discusses the process of solid body collisions involving simultaneous multipoint contact, which often occurs in agricultural machinery and related technologies. An analytical method is being developed to study such multiple-impact events, which can be applied to dynamic analyses of various high-speed production equipment and technological processes. The method is grounded in the fundamental laws of mechanics and limitations of object motion, utilizing an integral approach to determine impact parameters. Key examples illustrate the application of the proposed method to translational motion, and an analytical approach is presented for determining the rebound velocity of an object subjected to simultaneous impacts at multiple points. This approach requires prior knowledge of the pre-collision velocity, momentum restitution coefficients, and local linear elasticity coefficients at the points of contact. It also demonstrates how impact duration and average impact force can be estimated using local stiffness values and the object's mass. In cases involving rotational motion with straight thrust pulses at specified points, the rebound angular velocity is derived as a function of the initial angular velocity and the restitution coefficients. It is noted that the analysis remains applicable regardless of the number of collision points.
  • Pisipilt
    Kirje
    Wind power equipment for small farms and households
    (Estonian University of Life Sciences, 2024) Beresnevich, V.; Cerpinska, M.; Irbe, M.; Viba, J.
    This article deals with the development of small-sized wind power equipment as a viable solution for decentralized renewable energy production. To improve operational specifications of conventional turbine models with rotating blades, it is proposed to use a new design of wind power plant synthesized on the base of a closed loop conveyor equipped with flatshaped blades. In this design, blades are mounted on a belt with an opportunity to move together with it in one straight line direction. Air flow interaction with flat blade that performs translation motion is studied by computer simulation using a superposition principle. In accordance with this approach, a fast-chaotic motion of air particles (Brownian motion) is separated from the slow-directed air motion, with the given average velocity. Dynamic analysis of flat blade interaction with air flow is performed for the stationary air flow with constant speed and also for non-stationary flows with wind gusts. Optimization of the system parameters is made using the generated power as a criterion. Simulation results confirm the serviceability and efficient operation of the proposed conveyor type wind power equipment. It can be mounted on the roofs of buildings or rooftops of vehicles, also device is befriended to nature and people.