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Drive System Parameters Influence on Run-Up Process of the Drilling Rig Pumping Unit

Kovalchuk Roman, Molkov Yuriy, Lenkovskiy Taras, Grytsenko Oleksandr, Krasinskyi Volodymyr, Garbacz Tomasz

Advances in Science and Technology. Research Journal

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2018

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Vol. 12, no 4

199--206

EN

A mathematical model of dynamic processes in pumping unit of a drilling rig with friction clutch, taking into account variable moment of inertia of slider-crank mechanism links and random number of pistons of the pump, was developed. Joint integration of differential equations of motion of pumping unit parts was carried out with numerical methods. The calculations performed considered the torque moment of friction in the clutch and equations of electromagnetic processes in asynchronous motor. The results of research of run-up processes of pumping unit were presented. The influence of parameters of friction clutch on the performance of pumping unit was established.

2

Energy analysis of a mechanical system with a dynamic vibration absorber

Dobry M. W.

Vibrations in Physical Systems

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2016

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Vol. 27

83--90

EN

The study relates to the phenomenon of power distribution in mechanical systems equipped with a dynamic vibration absorber. It is one of the methods of eliminating vibrations in a mechanical system, which stabilises its operation. This solution helps to reduce dynamic stress in subsystems of a vehicle's suspension or stabilise the motion of flying machines, such as helicopters. The article describes the phenomenon of power distribution of structural forces, which has not been described so far. The phenomenon reveals the power distribution in a dynamic structure of a system of interest and can be used to determine the rate of energy flow as a function of the dynamic state resulting from the selection of dynamic parameters of the vibration absorber. The energy analysis applied in the study is based on an energy-based optimization method of adjusting the dynamic vibration absorber to the main mechanical system without changing its dynamic parameters, as is the case, for example, in turbine rotor balancing.

3

Influence of Material Damping on Dynamics of Slider-Crank Mechanism

Hać M.

Machine Dynamics Research

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2012

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Vol. 36, No. 2

16-25

EN

In this paper the dynamic analysis of a slider-crank mechanism is presented. It is taken into account the flexibility of links by applying finite element method with beam-type planar finite elements. The influence of material damping on dynamic behaviour of slider- crank mechanism is investigated. Mechanism is driven by variant torque applied to the crank and vibrational transient response is analysed. The midpoint deflection of the connecting rod as well as the displacement and velocity of slider are shown for the cases when Rayleigh proportional damping model is taken into account and for undamped vibration of links.

4

Positioning of Manipulator's Tip with Regard to Accuracy of Link Machining

Hać M., Kiszka K.

Machine Dynamics Research

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2011

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Vol. 35, No. 2

108-120

EN

In this paper the kinematic and dynamic analysis of planar two-link flexible manipulator is studied with the machining tolerance of links taken into account. The influence of different cross-section area within the assumed tolerance on the dynamic behaviour of manipulator's tip is investigated. For vibration analysis of links the finite element method is used with Bernoulli-Euler beam elements. The results of analysis show that the changes in the cross-sectional shape of manipulator's links, within the assumed tolerance of machining, can be quite significant and can influence the positioning accuracy of themanipulator. In order to obtain the exact trajectory of manipulator's tip the adaptive control system should be applied.

5

Modelowanie i symulacja numeryczna drgań młota udarowego RG-1

Klasztorny M., Niezgoda T., Gieleta R., Talarek P.

Biuletyn Wojskowej Akademii Technicznej

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2010

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Vol. 59, nr 4

313-334

PL

Przedmiotem modelowania i symulacji jest oryginalny młot udarowy sprężynowy o nazwie RG -1, zaprojektowany i wykonany w Katedrze Mechaniki i Informatyki Stosowanej Wydziału Mechanicznego Wojskowej Akademii Technicznej w Warszawie [1]. Opracowano nieliniowy dyskretny model dynamiczny układu młot-badany element energochłonny-wibroizolacja-fundament-podłoże i wyznaczono wartości parametrów tego modelu. Sformułowano nieliniowe równania ruchu układu w niejawnej postaci i opracowano algorytm numerycznego całkowania tych równań. Opracowano program komputerowy KESHA v2 do symulacji numerycznej drgań układu. Przeprowadzono wstępne badania numeryczne energochłonności elementów kompozytowych cylindrycznych. W celu redukcji drgań wywołanych pracą młota, urządzenie posadowiono na żelbetowym fundamencie blokowym za pośrednictwem wibroizolacji GERB, którą stanowi układ czterech wibroizolatorów sprężynowych z tłumikami wiskotycznymi, typu KV-452-247 03. Badany młot udarowy należy do klasy młotów o średnich prędkościach uderzenia i średniej energii uderzenia (vu = 2,5-11 m/s; Eu = 0,1-6,0 kJ).

EN

The study presents modelling and numerical simulation of the RG -1 spring stroke hammer, using the multi-body dynamics approach. The device has been designed and erected at the Laboratory of Strength of Materials of the Department of Mechanics and Applied Computer Science of Military University of Technology, Poland. The study develops a nonlinear discrete dynamic model of the hammer-examined specimen-vibroisolation-foundation-subsoil system as well as determines the values of the system parameters. A nonlinear matrix equation of motion of the system has been formulated partly in the implicit form, taking into consideration subsequent/simultaneous stages of the dynamic process, i.e., rapid release of the ram catch, expansion of the mainsprings, impact of the ram onto the examined specimen, shock absorption by the elastomeric pads, reduction of the forced vibrations by GERB vibroisolators, propagation of the vibrations in the subsoil, free damped vibrations of the system. An implicit algorithm for numerical integration of equations of motion, based on Newmark's average acceleration method, has been formulated. The problem has been reflected by a computer programme written in Pascal. The study presents numerical simulations reflecting dynamic tests of energy-absorbing composite cylindrical specimens. The ram fixed to the moving traverse is able to induce progressive failure up to the specimen length minus 15 mm. A distance of 15 mm is reserved for gathering the material of the destroyed part of the specimen. If this distance is achieved, the moving traverse strikes onto the elastomeric pads fixed to the cantilevers. All possible breakings away are taken into consideration in the matrix equation of motion. In order to reduce vibrations, induced by rapid releasing of the ram catch and by the main impact, the device has been connected to RC block foundation with four viscoelastic KV-452-247 03 GERB vibroisolation units. The fundamental natural frequency of the system is close to f1 = 3.4 Hz. The exemplary time histories of vibrations of select subsystems, corresponding to the initial shortening of the mainsprings equal to s = 75 mm and 150 mm, number of bobs n = 0, and the carbon/epoxy specimen CE-1, are shown in Figs. 10 and 11. The multi-body dynamic model of the device, the dynamic equation of motion, the computer algorithms and the computer programme constitute an effective tool for predicting energy absorption of composite specimens and for assessment of vibration isolation effectiveness. The GERB vibroisolation has appeared to be very effective. The investigated device belongs to the hammers class of the medium impact velocities (vu = 2.5-11 m/s) and the medium impact energy (Eu = 0.1-6.0 kJ).