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1
Obciążalność rozsuniętego teleskopowego siłownika hydraulicznego przy uwzględnieniu wyboczenia oraz wytężenia materiału
Uzny S., Kutrowski Ł.
Modelowanie Inżynierskie
|
2018
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T. 37, nr 68
125--131
PL
Uszkodzenia siłowników hydraulicznych mogą być spowodowane wieloma czynnikami. Można wśród niech wyróżnić utratę stateczności oraz wytężenie materiału cylindrów, wywołane działaniem wysokiego ciśnienia wewnątrz układu. W niniejszej pracy w celu rozpatrywania pierwszego z czynników sformułowano zagadnienie brzegowe stateczności teleskopowego siłownika hydraulicznego przy uwzględnieniu obciążenia Eulera. Do określenia wytrzymałości wytężeniowej poszczególnych członów siłownika wykorzystano teorię Lamégo w przypadku rur grubościennych. Zestawiając ze sobą uzyskane wyniki, określono zakresy parametru grubości cylindrów oraz parametru grubości elementów uszczelniających, przy których do zniszczenia układu dochodzi na skutek utraty stateczności konstrukcji lub wytężenia materiału cylindrów.
EN
Damage of the hydraulic cylinders can be caused by many factors. Loos of stability and material effort, caused by the pressure inside the cylinder barrels can be distinguished. For analysis of the first factor, boundary value problem of the stability of a hydraulic telescopic cylinder, subjected to Euler’s load was formulated. For determination of the strength of individual cylinders, the Lamé’s theory for thick pipes was used. By comparing obtained results, the ranges of the cylinder thickness parameter and the sealing elements thickness parameter were determined, in which the destruction of the system occurs as a result of the loss of stability of the structure and the effort of the cylinder material.
2
Content available remote The Effect of the Type of Mounting on Stability of a Hydraulic Telescopic Cylinder
Uzny S., Kutrowski Ł.
Machine Dynamics Research
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2018
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Vol. 42, No. 2
53--60
EN
This paper revolves around the boundary value problem regarding the stability of a telescopic hydraulic cylinder. The effect of its mounting type on the maximum load able to move without being damaged by buckling was examined. The formulation of the boundary problem was carried out on the basis of the static stability. The results were presented in a dimensionless form. The influence of the type of mounting of the telescopic hydraulic cylinder on the bearing capacity of the system was determined, taking into account changes in cylinder and seals thickness parameters and stiffness of connections between following elements. The results are presented for a three-stage and a five-stage hydraulic telescopic cylinder.
3
Content available On bifurcation load of a three-member slender system with an internal crack subjected to Euler’s load
Uzny S., Sokół K.
Journal of Theoretical and Applied Mechanics
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2018
|
Vol. 56 nr 1
269--281
EN
The results of numerical simulations presented in this paper are concerned with instability of a three member slender system subjected to Euler load. The investigated column is built up as a flat frame composed of three rods. In the internal one, the defect is present in form of a crack. The boundary problem has been formulated on the basis of a static criterion of instability. The boundary conditions associated with different types of supports are obtained by proper selection of parameters of the generalized load. On the basis of these results, the magnitude of bifurcation load can be determined.
4
Drgania swobodne teleskopowego siłownika hydraulicznego poddanego obciążeniu Eulera
Uzny S., Kutrowski Ł.
Modelowanie Inżynierskie
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2017
|
T. 33, nr 64
108--113
PL
W niniejszej pracy przedstawiono zagadnienie brzegowe dotyczące drgań swobodnych teleskopowego siłownika hydraulicznego jednostronnego działania, poddanego obciążeniu Eulera. Na podstawie zagadnienia brzegowego, sformułowanego na podstawie kinetycznego kryterium stateczności (przy wykorzystaniu zasady Hamiltona) przeprowadzono obliczenia dotyczące drgań poprzecznych układu. W pracy rozważano siłownik zamocowany przegubowo na obydwu jego końcach. Wyniki obliczeń numerycznych otrzymane na podstawie zagadnienia brzegowego przedstawiono w postaci bezwymiarowej. Określono wpływ parametrów siłownika (parametry grubości cylindrów oraz grubości uszczelnień) na wartość pierwszej częstości drgań własnych układu. Wyniki przeprowadzonych symulacji numerycznych przedstawiono w postaci krzywych charakterystycznych (krzywych na płaszczyźnie obciążenie – częstość drgań własnych).
EN
This thesis revolves around boundary value problem involving free vibrations of a hydraulic telescopic single acting cylinder, subjected to Euler’s load. Calculations concerning free transverse vibrations were performer based on boundary value problem, formulated in reference to kinetic stability criterion (using Hamilton’s principle). In this paper hydraulic cylinder was considered to be a simply supported system. The results, based on boundary value problem, were presented in non-dimensional form. Influence of cylinder parameters (parameter of cylinder thickness and sealing thickness) on first natural frequency were determined in this paper. The results of numerical simulations were presented on characteristic curves (curves in the plane load – natural frequency).
5
Content available The effect of torsional rigidity between elements on free vibrations of a telescopic hydraulic cylinder subjected to Euler’s load
Uzny S., Kutrowski Ł.
Journal of Applied Mathematics and Computational Mechanics
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2017
|
Vol. 16, nr 3
117--122
EN
The boundary problem of free vibrations of a hydraulic telescopic cylinder, subjected to Euler’s load was presented in this work. The task was formulated on the basis of the Hamilton’s principle. The computational model, formulated by Tomski, was taken into account during analysis. Numerical calculations concern free vibrations of multi-stage hydraulic telescopic cylinder. Results were presented in the form of characteristic curves on the plane: external load-natural vibration frequency. Non-dimensional parameters of the structure were defined in reference to the characteristic parameters of the piston rod. During numerical simulations, an influence of a non-dimensional stiffness parameter between following elements on free vibrations of a hydraulic telescopic cylinder was determined for a different number of cylinder stages.
6
Content available Load by a force directed towards a positive pole in the aspect of studies on vibrations of a column with crack
Sokół K., Uzny S.
Vibrations in Physical Systems
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2016
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Vol. 27
325--332
EN
In this paper the results of numerical studies on natural vibration frequency and stability of a slender supporting system loaded by external force directed towards a positive pole are presented. In the investigated structure the failure in the form of crack is present. The boundary problem is formulated on the basis of the principle of minimum action – Hamilton’s principle. The results in the non-dimensional form are plotted as the characteristic curves in the external load – natural vibration frequency plane as well as the maximum loading capacity is discussed.
7
Content available Free vibrations of the partially tensioned geometrically non-linear system subjected to Euler’s load
Uzny S., Sokół K., Osadnik M.
Vibrations in Physical Systems
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2016
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Vol. 27
399--406
EN
In this study the fixed-fixed column subjected to axial Euler’s load has been investigated. The load is placed between the fixed ends of the structure and its location can be changed along column’s length. The boundary problem of free vibrations of the mentioned system has been formulated on the basis of Bernoulli – Euler theory and taking into account non-linear axial deformation relationship. Due to non-linear expressions the solution of the problem was done with small parameter method. In the paper the change of the first vibration frequency in relation to location and magnitude of the loading force was obtained. The relationship between natural vibration frequency and the amplitude is also discussed.
8
Content available Numerical studies on stability of slender supporting structures
Sokół K., Uzny S.
Journal of Applied Mathematics and Computational Mechanics
|
2016
|
Vol. 15, nr 2
157--165
EN
In this paper the results of studies on stability of the geometrically non-linear column (slender system) composed of two rods have been presented. The supporting structure has a defect in the form of cracks which are present in each of rods. The cracks are simulated by means of rotational springs. On the basis of the total potential energy principle, the boundary problem is being formulated. The results show an influence of the crack size on the stability of the column in particular on bifurcation load magnitude.
9
Content available remote Modelling and Simulation Research of the Gripper Manipulator
Uzny S., Sokół K.
Machine Dynamics Research
|
2015
|
Vol. 39, No. 2
5-14
EN
In this paper the boundary problem of instability of single slender system with consideration of Timoshenko theory is presented. The investigated structure is loaded by Euler’s force (the most common type of loading); additionally the different boundary conditions are taken into account. Simulated type of external load is characterized by constant line of action regardless to deflection of the system. In order to achieve more general form of the investigated system the springs limiting the rotations and displacement of both ends are used. Boundary problem is formulated on the basis of the minimum total potential energy. The results of numerical simulations obtained with Timoshenko and Bernoulli-Euler theories are compared. The simulations are done at different magnitudes of slenderness factor as well as translational and rotational springs stiffness. On the basis of the obtained results the difference in critical forces calculated on the basis of both theories can be easily presented.
10
Content available remote An Influence of Cracks Location on Instability of a Multi-Member Cantilever Slender Supporting System
Sokół K., Uzny S.
Machine Dynamics Research
|
2015
|
Vol. 39, No. 3
59-68
EN
In this publication the nonlinear slender cantilever column composed of two rods in which the cracks are present is investigated. The cracks are simulated by means of rotational springs with linear characteristic. Additionally the external compressive load is located at the free end to the structure. In order to predict the static behaviour of the column the boundary problem is being formulated by means of the principle of total potential energy. The results of numerical simulations are concern on influence of the locations of cracks on loading capacity. On the basis of the analysis of the results the most dangerous (lowest loading capacity) regions are found.
11
Content available Free vibrations of column subjected to Euler's load with consideration of Timoshenko's theory
Uzny S., Sokół K.
Vibrations in Physical Systems
|
2014
|
Vol. 26
319--326
EN
In this paper the single-rod cantilever column subjected to compressive Euler's load is investigated. The boundary problem has been formulated on the basis of Hamilton's principle and Timoshenko's theory. Numerical simulations of characteristic curves have been plotted on the plane external load-vibration frequency for different magnitudes of slenderness factor of the system. The results of numerical calculations of Timoshenko's beam are compared to the ones obtained from mathematical Bernoulli-Euler's model. The comparison of the results of characteristic curves calculated by means of Timoshenko's theory and Bernoulli-Euler's model are done for first three vibration frequencies.
12
Content available Free vibrations of column built out pipe and rod with two-parametric elastic connector
Uzny S.
Vibrations in Physical Systems
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2014
|
Vol. 26
311--318
EN
In this paper the geometrically nonlinear system subjected to compressive external Euler's load has been investigated. The column is composed of pipe and rod. The rod is concentrically installed in the pipe. Between pipe and rod at given distance from the end of the column the two-parametric elastic connector has been placed. The numerical calculations were performed for different parameters of the system on the basis of free vibration boundary problem. The parameters are as follows: spring stiffness (translational and rotational) which models elastic connector, coefficient of asymmetry flexural rigidity, location of the connector.
13
Content available remote The Regions of Local and Global Instability of a Two-Member Slender System with Grack
Uzny S., Sokół K.
Machine Dynamics Research
|
2014
|
Vol. 38, No. 2
75-83
EN
In this paper the instability phenomenon of a column composed of two elements with different bending and compression stiffness's is presented. In the one of elements the crack modeled by means of rotational spring with linear characteristic is present. The boundary problem of an instability has been formulated on the basis of the minimum total potential energy principle. In this study only the results corresponding to the magnitude of bifurcation loading of the two element system are presented (rectilinear form of static equilibrium). These results were compared to the critical loading magnitude calculated for single element system (a system without crack). Finally the comparison of the bifurcation loading of a two element system to the single element one under consideration of different magnitudes of bending rigidity factor allows one to present the regions of local and global instability of the considered complex system.
14
Content available remote Vibrations and Stability of a Column Subjected to the Specific Load Realized by Circular Elements of Heads
Tomski L., Uzny S.
Mechanics and Mechanical Engineering
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2013
|
Vol. 17, nr 2
197--206
EN
Research into columns subjected to a specific load considering a constructional solution consisting of circular elements is an aim of the paper. The boundary problem of stability and free vibrations of the considered system for a generalised load by a force directed towards the positive pole was formulated on the basis of Hamilton’s principle. The boundary conditions concerning the load by a follower force directed towards the positive pole were deduced on the basis of the boundary conditions of the column subjected to a generalised load by a force directed towards the positive pole. In this paper, the load by the follower force was treated as a special case of the generalised load by a force directed towards the positive pole. Apart from the formulation of and solution to the boundary problem of the columns subjected to the specific load, the results of numerical computations connected to the static problem and free vibrations of the considered systems were also presented.
15
Content available remote Vibrations of a column consisting of a pipe and rod with a viscoelastic layer subjected to Euler’s load
Uzny S.
Vibrations in Physical Systems
|
2012
|
Vol. 25
435--440
EN
The boundary problem concerning the free vibrations of a geometrically non-linear slender system subjected to a load by a force, unchanging in its direction (Euler’s force), is formulated and solved in the work. The considered column is a pipe with a focally mounted rod. A layer made of viscoelastic material is placed between the pipe and the rod. The Kelvin-Voigt model of this layer is taken into account to formulate the boundary problem. Numerical calculations connected to the free vibrations of the considered system are carried out on the basis of the boundary problem. Numerical simulations are assigned to different values of the parameters of the system for which the rigidity and damping parameters of the viscoelastic layer are ranked.
16
Content available remote The regions of divergence and flutter instability of a column subjected to beck’s generalized load taking into account an elastic support at the loaded end
Tomski L., Uzny S.
Vibrations in Physical Systems
|
2012
|
Vol. 25
423--428
EN
The boundary value problem concerning the free vibrations of a slender system subjected to Beck’s generalized load was formulated and solved in the work. The considered column was elastically supported by a spring with linear characteristic at the loaded end. The critical load of the system, both divergence and flutter, and the regions of presence of divergence and flutter instability were determined on the basis of the boundary problem concerning the free vibrations (the kinetic criterion of stability). Numerical calculations have been assigned to different values of the parameters of the considered system for which the follower factor, the rigidity parameter of a spring supporting column, the parameter of the translational inertia of the body mounted at the loaded end of the column are ranked.
17
Nieliniowa składowa częstości drgań własnych kolumny poddanej obciążeniu Eulera (krzywoliniowa postać równowagi statycznej)
Uzny S.
Modelowanie Inżynierskie
|
2011
|
T. 11, nr 42
441-448
PL
W pracy rozważa się drgania smukłego układu geometrycznie nieliniowego wokół krzywoliniowej postaci równowagi statycznej. Układ poddano działaniu ściskającej siły zewnętrznej Eulera. Na podstawie zagadnienia brzegowego przeprowadzono obliczenia numeryczne dotyczące liniowej i nieliniowej składowej częstości drgań własnych, które wykonano przy różnych wartościach parametrów układu.
EN
Boundary value problem concerning to free vibrations of geometrically nonlinear slender system subjected to compressed external Euler force was formulated and solved in this work. On account nonlinearity the small parameter method has been used. In this work curvilinear form of static equilibrium is considered. On the basis of boundary value problem the calculations concerning to linear and nonlinear components of free vibrations frequency have been carried out. Numerical calculations was carried out at different values of system parameters.
18
Nieliniowa składowa częstości drgań własnych kolumny poddanej obciążeniu Eulera (prostoliniowa postać równowagi statycznej)
Uzny S.
Modelowanie Inżynierskie
|
2011
|
T. 11, nr 42
449-456
PL
W pracy sformułowano i rozwiązano zagadnienie brzegowe dotyczące drgań własnych smukłego układu geometrycznie nieliniowego poddanego działaniu ściskającej siły zewnętrznej Eulera. Ze względu na nieliniowość wykorzystano metodę małego parametru. Rozważaniom poddano prostoliniową postać równowagi statycznej. Na podstawie zagadnienia brzegowego przeprowadzono obliczenia numeryczne dotyczące liniowej i nieliniowej składowej częstości drgań własnych. Obliczenia numeryczne wykonano przy różnych wartościach parametrów układu.
EN
Boundary value problem concerning to free vibrations of geometrically nonlinear slender system subjected to compressed external Euler force was formulated and solved in this work. On account of nonlinearity the small parameter method has been used. In this work rectilinear form of static equilibrium is considered. On the basis of boundary value problem the calculations concerning to linear and nonlinear components of free vibrations frequency have been carried out. Numerical calculations was carried out at different values of system parameters.
19
Content available remote A hydraulic cylinder subjected to Euler's load in aspect of the stability and free vibrations taking into account discrete elastic elements
Tomski L., Uzny S.
Archives of Civil and Mechanical Engineering
|
2011
|
Vol. 11, no 3
769-785
EN
Theoretical and numerical research into the stability and free vibrations of a slender system in the form of a hydraulic cylinder subjected to Euler's load was carried out in this paper. The rigidities in the constructional nods realising the load of the considered system were taken into account in the system. Both rotational and translational springs were applied to the loading nods. Regions of the flexural rigidity asymmetry factor for the piston rod and cylinder, where the system is subject to damage as a result of stability loss, were determined in the frame of numerical research into the hydraulic cylinder. In this paper critical load and characteristic curves were also determined in the plane: load-natural frequency. These two quantities were determined for different parameters of the system: the flexural rigidity asymmetry factor for the piston rod and cylinder, the degree of coverage of cylinder, the rigidities of the rotational and translational springs, and the total rigidity factor of the system.
PL
W niniejszej pracy przeprowadzono badania teoretyczne i numeryczne dotyczące stateczności i drgań własnych smukłego układu w postaci siłownika hydraulicznego, który poddano obciążeniu Eulera. W układzie uwzględniono sztywności w węzłach konstrukcyjnych realizujących obciążenie rozważanego układu. W węzłach obciążających zastosowano sprężyny rotacyjne jak i translacyjne. W ramach badań numerycznych siłownika hydraulicznego określono obszary współczynnika asymetrii sztywności na zginanie tłoczyska i cylindra, przy których układ ulega zniszczeniu w wyniku utraty stateczności. W pracy wyznaczono również obciążenie krytyczne oraz krzywe charakterystyczne na płaszczyźnie obciążenie - częstość drgań własnych. Te dwie wielkości wyznaczono przy różnych wartościach parametrów układu, do których zalicza się współczynnik asymetrii sztywności na zginanie tłoczyska i cylindra, stopień przekrycia siłownika, sztywności sprężyn rotacyjnych i translacyjnej oraz współczynnik całkowitej sztywności układu.
20
Content available remote Wybrane przypadki zamocowań siłowników hydraulicznych poddanych obciążeniu Eulera w aspekcie stateczności i drgań własnych
Tomski L., Uzny S.
Górnictwo Odkrywkowe
|
2010
|
R. 51, nr 3
219-223
PL
W niniejszej pracy przeprowadzono badania teoretyczne i numeryczne dotyczące stateczności i drgań własnych smukłego układu w postaci siłownika hydraulicznego, który poddano obciążeniu Eulera. Rozpatrywano sześć możliwości zamocowania siłownika. Na podstawie zagadnienia brzegowego przeprowadzono szereg symulacji numerycznych. Wyznaczono obciążenie krytyczne oraz krzywe charakterystyczne na płaszczyźnie obciążenie - częstość drgań własnych w zależności od parametrów układu.
EN
Theoretical and numerical research concerned to stability and free vibrations of slender system inform of hydraulic cylinder which was subjected to Euler load were made in this work. Six possibility offbced of hydraulic cylinder were considered in the paper. On the basis of the boundary problem a lot of numerical simulations were carried out. Critical load and characteristic curves on the plane load - natural frequency were determined in dependence on parameters of considered system. Coefficient of asymmetry flexural rigidity of piston rod and cylinder, coefficient of overlap and external load were used in the numerical calculations. Moreover limiting value of coefficient of asymmetry flexural rigidity piston rod and cylinder was determined in the work. Limiting value of coefficient of asymmetry flexural rigidity separated two regions. Hydraulic cylinder breaks down in result of lost of stability in first region . Hydraulic cylinder breaks down in result of effort of cylinder material in second region. Stress of part of cylinder which was filled by liquid was calculated on the basis of the Lame theory.
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