Róbert Németh

Róbert Németh
Budapest University of Technology and Economics · Department of Structural Mechanics

PhD

About

24
Publications
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61
Citations
Introduction

Publications

Publications (24)
Article
Full-text available
This paper introduces a new solution method based on modal analysis to calculate periodic nonlinear response to harmonic forcing. The method can be used for piecewise linear (PL) elastic multi-degree-of-freedom (MDOF) systems with two linear states, provided that the unloaded equilibrium position of both states coincides, and the system is in both...
Article
Modal analysis is an often-used method for the solution of dynamical problems in engineering practice. In the case of continuous systems and discretization methods (e.g., FEM) with a large number of degrees of freedom, the reduced modal analysis is used, where only a selected number of modes are applied, while the higher modes are neglected. A piec...
Article
Historically, the first groin vaults were built without ribs, but ribs later appeared for various reasons. Some ribs have only an aesthetic role, while others have a clear structural role in stiffening the groin. The stiffening effect on the static behavior is currently of wide interest, as the preservation of architectural heritage has become impo...
Article
Full-text available
In this paper the dynamic analysis of a beam on a block-and-tackle suspension system is accomplished using a continuum approach. The modal shape functions and the natural frequencies of the structure are derived in a dimensionless form for both slacked and stressed cables. A procedure is developed to handle the nonlinearity originated from the cons...
Article
Full-text available
In this paper, the free vibration and the buckling of a continuously suspended simply-supported beam are analyzed. A semi-analytical approach is used to calculate the natural circular frequencies and the critical forces of the beam. The length of the suspension is used as a parameter, and the natural circular frequencies and the critical forces are...
Article
Full-text available
In this paper, the dynamic behaviour of a family of piecewise linear structures, namely the vibration of beams on block-and-tackle suspension system is analysed. The regularity of the vibration modes in one of the linear states induces non-harmonic, yet periodic free vibration modes. The periodicity constraint of the continuous structure is formula...
Article
The paper investigates the energy- and amplitude-dependent natural periods of symmetrically cracked semi-circular arches, which are loaded by their self-weight and horizontal support displacement. The cracks appear due to previous static effects. Symmetric free vibration of the arches is under analysis. The symmetry condition results in an SDoF sys...
Article
In this paper the effects of a new kind of structure, the block-and-tackle suspension system, are investigated on the free vibration of a beam family subjected to bending. The beam family consists of symmetric pinned-pinned beams that are supported by an infinitely stiff cable with neglectable mass connected symmetrically by the block-and-tackle sy...
Article
In this paper the effects of a new kind of structure, the block-and-tackle suspension system is investigated on the free vibration of a beam family subjected to bending. The beam family consists of symmetric pinned-pinned beams that are supported by an infinitely stiff cable with neglectable mass connected symmetrically by the block-and-tackle syst...
Article
The paper investigates the natural periods of symmetrically cracked semi-circular masonry arches. The cracks are present due to previous actions, additionally new cracks do not appear and the depth of the cracks do not change during motion, which assumptions are acceptable, if the amplitude of the vibration is relatively small. During vibration the...
Article
Full-text available
In this work the dynamical analysis of a pre-stressed continuous rod with one crack at the end is carried out. This kind of behaviour is typical for masonry and concrete structures, which have low tensional resistance. An initial crack is assumed at the end of the bar. The longitudinal vibration in this structure will be performed with the modal an...
Conference Paper
Full-text available
Munkánkban a csak nyomásnak ellenálló anyagú húzott-nyomott rúd diszkrét modelljének dinamikai vizsgálatát végezzük el. Ilyen anyagként modellezhető például a beton, vagy a falazott szerkezetek, melyek húzószilárdsága jóval alacsonyabb, mint a nyomószilárdsága. Ezen anyagok folytonossága már alacsony húzóerő hatására megszűnik, repedések jelennek m...
Article
Full-text available
In this paper a discrete model, the bielastic web of links is introduced and analysed with respect to its static equilibrium states, buckling and stability under compression. Analytical solutions are derived for the buckling loads of the trivial, purely compressed equilibrium state of the structure, and for the geometry of the buckled configuration...
Article
Full-text available
Solution of mechanical problems often requires the analytical or numerical calculation of equilibrium paths, while multidimensional solution sets are rare. From this requirement emerged numerous methods for the calculation of bifurcation diagrams. Two large groups of solution methods are the continuation methods and the scanning methods (however hy...
Article
Full-text available
Spatially chaotic bifurcations of an elastic web of links are investigated. We numerically construct the global bifurcation diagrams uniquely describing the buckled states, and show that the exponential growth of the number of equilibrium branches with the size of the web indicates spatial chaos. The types of bifurcations from the trivial equilibri...
Article
Full-text available
The Kirchhoff rod is a widely used model in the describing configurations of DNA chains. In the simplest case of such research the molecule-chain is represented by a twisted-bent rod. In this paper we will present an application of this rod model for describing the shapes of the DNA chain in a special configuration. Here, two finite segments of the...
Article
Full-text available
A discrete model consisting N straight links and N springs is defined. The originally straight model is bent into a discrete torus, then it is twisted. The C2 symmetric shapes can be determined by four parameters, and there are three constrains. The equilibrium paths are determined by the simplex method (piecewise linear approximation). Global bifu...
Article
Full-text available
Ha egy viszkoelasztikus szerkezetet allando teherrel megterhelunk, akkor altala- ban a terheles pillanataban letrejon egy rugalmas alakvaltozas, majd valtozatlan te- her eseten is tovabbi deformacio alakul ki. Itt, es a tovabbiakban, feltetelezzuk, hogy a terheles kvazistatikus, vagyis olyan lassan jut a teher a szerkezetre, hogy a letrejovő elmozd...
Article
A mérnöki gyakorlathoz kapcsolódó mechanikai problémák sok esetben vezetnek nemlineáris numerikus feladatra. Ilyen feladatot jelent többek között a szerkezetek stabilitásvizsgálata, a nagy elmozdulásokkal kapcsolatos vizsgálatok, illetve geodéziai eredetű számítási problémák is. Kutatásaink során megmutattuk, hogy rugalmas szerkezetek stabilitásána...

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