Some research topics of the department

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Nonlinear behavior of RC columns

Project leader: Prof. László Kollár

Member: Bernát Csuka

Geometry, shape dynamics, and classification of particles subject to abrasive processes (OTKA Grant 72146)

koptatottWe analyze the geometrical properties of particles  (pebbles, sand, asteroids) in abrasive processes. Our goal is to understand their shape evolution as well as to work out statistical methods that provide information on the geological history of a particle set based on its geometrical properties

Project leader: Domokos Gábor,domokos_at_iit.bme.hu

Members: Buella Csaba, Sipos András, Szabó Tímea, Várkonyi Péter

Photo:  Wind-worn rock with sharp edges and flat faces.Photo: Matthias Braunlich, Hamburg (www.kristallin.de)

Global computation and qualitative decsription of nonlinear boundary value problems

domokos-kabel

This research targeted a broad area, however, eight specific goals have been set and we could achieve these goals. Our results on uplift-buckling of the elastic strip may help to understand the nonlinear mechanics of long cables on the ocean floor. We found a surprisingly simple mechnaical model capable of describing the spatially highly complex shapes of botanical filaments. Our reserach on slightly asymmetric optima of reinforced concrete structures identified new, non-trivial types of solutions in structural optimization. We investigated the relationhsoip between discrete and continuous models in population dynamics. Our results show that the question, whether discrete models should be applied can be only decided by careful analysis of the environmental noise. We investigated the role of effective dimensions in chemical transients in closed chaotic flows and we could identify the effect of dispersion on the cyclic competition of microorganisms.
We also investigated how fractal scaling of microbial colonies affects growth and found that instead of density, fractal dimension is the best descriptor of these colonies.

Project leader: Domokos Gábor, domokos_at_iit.bme.hu

Members: Sipos András Árpád

Shear design of RC beams by vaulted substitutive lattice model

vasbeton

The goal of the research project is to improve upon the variable strut inclination method for shear design of Eurocode 2. The research includes theoretical modeling and experimental tests.

Project leader: András Draskóczy,

drasko_at_silver.szt.bme.hu

Symmetry and bifurcations of optima

domokos-optimumdiagram

In this project we investigated the relationship between symmetry and optima in the context of engineering structures, evolutionary processes and population dynamics. In case of engineering structures we found that symmetric structures can be often improved by introducing small asymmetres. We formulated a group-theoretic criterium to decide whether a given structure could be potentially improved in the space of given symmetry-breaking variables. We illustrated our results on simple examples, we also provided an example close to practical engineering. We studied evolution in the framework of adaptive dynamics and described the symmetry-breaking bifurcations in this process. We also provided biological examples for symmetry-breaking. We investigated discrete population models and showed that a discrete population can produce chaotic behaviour only in the presence of environmental noise.

Project leader: Gábor Domokos

Members: András Á. Sipos, Péter Várkonyi

Duration: OTKA 49885, 2005 - 2008

Geometric imperfections and nonlinear response of trusses

racsos

We analyze statically determinate and indeterminate trusses. Our goal is to answer the three questions below:

- How do the (very small) normal force and its sign depends on the load parameter in zero-force members?

- In which bars is the normal force influenced by the imperfect location of a joint?

- Is it possible to find asymmetric optima among statically determinate structures?

Project leader: Gábor Domokos, domokos_at_iit.bme.hu

Member: Krisztina Tóth

Size effects in the ductile behavior of RC structures

vajkrita

Project leader:Dr. István Sajtos,sajtos_at_silver.szt.bme.hu         

 

Members: Rita Vajk

Figure: Moment-curvature diagram of an RC member made of  aggregates of various sizes 

The role of mechanical interactions in generating collective motion (part of OTKA 72368 )

VP-falka

Groups of fish, birds, bacteria, and other moving creatures often show organized patterns, which are generated by simple interactions of individuals. The design of similar artificial systems is also a fast developing area of robotics. My goal is to understand, how collisions, contact, and collision avoidance strategies contribute to collective motion, and to learn about the propagation of information about motion preferences via mechanical interactions

Project leader: Péter Várkonyi (vpeter_at_mit.bme.hu)

Picture: Simulation of self-propelled rigid objects subject to attraction, and hard, inelastic collisions. Click to plot to view video (9 MB, H.264 compression)

Objects that never capsize: mechanical and geometrical aspects of spontaneous self-righting

teknos

If dropped onto a plane, most objects stop in one of several stable equilibrium positions. Alternatively they may not stop at all, if the plane is not horizontal. Our goal is to design, and analyze self-righting objects that do stabilize in a unique position regardless of the initial conditions. The existence of such shapes not only represents intriguing mathematical questions, but it has a wide field of application from turtle morphology to robotics.

Project leader: Gábor Domokos (domokos_at_iit.bme.hu)

Members: Péter Várkonyi

Photo: An object that does capsize: Benő the turtle (by Tímea Szabó)

Design and calculation of structures made of hot rolled steel section based on the EUROCODE 3

hengereltThe main goals of the project are:

- Analyzing the effect of EUROCODE 3 on the production of steel structures in Hungary.

- Comparison of the old and new regulations.   

- Development of tables, diagrams to help economic structural design.

- Development of simplified and approximate methods in the field of lateral torsional buckling, end-plated connection, structures with semi-rigid connections.

- Methodology for designers.

Project leader: Sándor Fernezelyi

fernezelyi_at_silver.szt.bme.hu

Members: Árva Péter, Csuka Bernát, Erdélyi Tamás, Hegyi Dezső, Sipos András, Vető Dániel, Vigh Attila, Visnovitz György,

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