Brno, Czech Republic

Brno University of Technology

www.vutbr.cz/en
Brno, Czech Republic

Brno University of Technology is a university located in Brno, Czech Republic. Being founded in 1899 and initially offering a single course in civil engineering, it grew to become a major Czech university with over 24,000 students enrolled at 8 faculties and 2 university institutes. Wikipedia.

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Patent
R.Ø.S.A. and Brno University of Technology | Date: 2017-01-04

The invention relates to a parameterizable merging unit for sensor-based measurement of current and voltage in high voltage networks or electrical grids operating with other voltage levels, according to the preamble of claim 1 and 14. In order to t enhance the electronical unit and the method to operate the same, in such, to result in a higher vulnerability of such systems to ambient disturbancy in an easy and constructively compact way, and to improve the measurement accuracy with that, the invention is, the aforesaid unit contains memory or storage means for coefficients for the correction of one and/or more basic characteristics of current and/or voltage sensors, with basic characteristics denoting static transfer-, temperature-, frequency-, load-, and position characteristics.


Elias J.,Brno University of Technology
Materials | Year: 2017

The paper studies systems of rigid bodies with randomly generated geometry interconnected by normal and tangential bonds. The stiffness of these bonds determines themacroscopic elastic modulus while the macroscopic Poisson's ratio of the system is determined solely by the normal/tangential stiffness ratio. Discrete models with no directional bias have the same probability of element orientation for any direction and therefore the same mechanical properties in a statistical sense at any point and direction. However, the layers of elements in the vicinity of the boundary exhibit biased orientation, preferring elements parallel with the boundary. As a consequence, when strain occurs in this direction, the boundary layer becomes stiffer than the interior for the normal/tangential stiffness ratio larger than one, and vice versa. Nonlinear constitutive laws are typically such that the straining of an element in shear results in higher strength and ductility than straining in tension. Since the boundary layer tends, due to the bias in the elemental orientation, to involve more tension than shear at the contacts, it also becomes weaker and less ductile. The paper documents these observations and compares them to the results of theoretical analysis. © 2017 by the authors.


Kala Z.,Brno University of Technology
Thin-Walled Structures | Year: 2011

The objective of the paper is to analyse the influence of initial imperfections on the load-carrying capacity of a single storey steel plane frame comprised of two columns loaded in compression. The influence of the variance of initial imperfections on the variance of the load-carrying capacity was calculated by means of Sobol' sensitivity analysis. Monte Carlo based procedures were used for computing full sets of first order and second order sensitivity indices of the model. The geometrical nonlinear finite element solution, which provides numerical results per run, was employed. The mutual dependence of sensitivity indices and column non-dimensional slenderness is analysed. The derivation of the statistical characteristics of system imperfections of the initial inclination of columns is described in the introduction of the present work. Material and geometrical characteristics of hot-rolled IPE members were considered to be random quantities with histograms obtained from experiments. The Sobol sensitivity analysis is used to identify the crucial input random imperfections and their higher order interaction effects. © 2010 Elsevier Ltd. All rights reserved.


Kala Z.,Brno University of Technology
Engineering Structures | Year: 2011

The article presents the sensitivity and statistical analyses of the load-carrying capacity of a steel portal frame. It elaborates a typical stability problem of a system comprising two single-storey columns loaded in compression. The elements of this system mutually influence each other, and this fact, in conjunction with the random imperfections, influences the load-carrying capacity variance. This mutual interaction is analysed using the Sobol' sensitivity analysis. The Sobol' sensitivity analysis is applied to identify the dominant input random imperfections and their higher order interaction effects on the load-carrying capacity. Majority of imperfections were considered according to the results of experimental research. Realizations of initial imperfections were simulated applying the Latin Hypercube Sampling method. The geometrical nonlinear solution providing numerical result per run was employed. The frame was meshed using beam elements. The columns of the plane frame are considered with two variants of boundary conditions. The dependence between mean and design load-carrying capacities and column non-dimensional slenderness is analysed. © 2011 Elsevier Ltd.


Kala Z.,Brno University of Technology
Journal of Civil Engineering and Management | Year: 2012

The random load carrying capacity of steel plane frames with bracing stiffness is studied. The load carrying capacity is evaluated using the geometrically non-linear FEM analysis. The incremental stiffness matrix of a slightly curved element utilized in the non-linear incremental analysis is listed. Initial imperfections are considered as random variables. Statistical analysis and Sobol sensitivity analysis are performed using the Latin Hypercube Sampling method. The effect of initial random imperfections on the load carrying capacity is studied, whilst assuming constant slenderness of the columns. The evaluation parameters are the pair of non-random values of elastic bracing stiffness, and system length of the columns. The paper illustrates that the load carrying capacity is very sensitive to initial crookedness of the columns in the event that the non-sway (symmetric) and sway (anti-symmetric) buckling modes coincide. In this case, the design load carrying capacity obtained from statistical analysis according to the EN 1990 (2002) standard is relatively very small (of low safety). Results show that the reliability of design of a steel frame according to EUROCODE 3 (1993) is significantly misaligned. The significance of the first and the second buckling forces as indicators of sensitivity of the load carrying capacity to the imperfections is discussed. Copyright © 2012 Vilnius Gediminas Technical University (VGTU) Press Technika.


Druckmuller M.,Brno University of Technology
Astrophysical Journal, Supplement Series | Year: 2013

A new image enhancement tool ideally suited for the visualization of fine structures in extreme ultraviolet images of the corona is presented in this paper. The Noise Adaptive Fuzzy Equalization method is particularly suited for the exceptionally high dynamic range images from the Atmospheric Imaging Assembly instrument on the Solar Dynamics Observatory. This method produces artifact-free images and gives significantly better results than methods based on convolution or Fourier transform which are often used for that purpose. © 2013. The American Astronomical Society. All rights reserved.


Rovnanik P.,Brno University of Technology
Construction and Building Materials | Year: 2010

The properties of metakaolin-based geopolymer are directly impacted not only by the specific surface and composition of initial metakaolin and the type, composition and relative amount of alkali activator used but they also depend on the conditions during the initial period of geopolymerization reaction. This study aimed to analyze the effect of curing temperature (10, 20, 40, 60 and 80 °C) and time on the compressive and flexural strengths, pore distribution and microstructure of alkali activated metakaolin material. The results have shown that the treatment of fresh mixture at elevated temperatures accelerates the strengths development but the 28 days mechanical properties are deteriorated in comparison with results obtained for mixtures that were treated at an ambient or slightly decreased temperature. The influence of curing temperature on microstructure of geopolymer matrix was verified in terms of pore distribution studied by means of mercury intrusion porosimetry. The study revealed a tendency to increase pore size and cumulative pore volume with rising temperature, which is reflected in mechanical properties. It has been also shown the possibility of monitoring the geopolymerization reaction by means of Infrared Spectroscopy. © 2009 Elsevier Ltd. All rights reserved.


Patent
Brno University of Technology | Date: 2014-09-30

An abrasion resistant material includes a polymeric matrix composite, preferably an amorphous thermoplastic or a resin containing homogenously dispersed nanoparticles ranging in size from 1 to 50 nm, further combined with clusters of the nanoparticles, or a combination of nanoparticles of different sizes within the above-stated range. A method of preparation of, and automotive parts containing, this material are also disclosed.


Patent
Airbus and Brno University of Technology | Date: 2014-06-11

A device 10 for testing the effect of impacts on a test object 22 exposed to a fluid flow 89 in wind tunnel apparatus 26 is described. Also a testing method for testing the effect of impact is provided. The device 10 uses pressurized fluid to accelerate an insect 14, insect model 16 or ice crystal 17 up to an air speed inside the wind tunnel apparatus 26 and guides the insect 14, insect model 16 or ice crystal 17 to a desired target area 23 on the test object 22.


Patent
Brno University of Technology | Date: 2014-09-30

A material for ballistic protection includes multiple compact layers of ballistic fiber and, between the layers of ballistic fibers, inserted at least one intermediate layer of non-Newtonian fluid exhibiting an increase in viscosity resulting from an increase in shear stress optionally containing particles having the size of from 1 to 700 nm or antiplasticizing agents. The intermediate layer is placed either directly between layers of ballistic fiber or between the layers on a packing or a perforated packing or applied on a fabric. A method of preparation of the material is also disclosed. This material is flexible and has a low weight and can be used, in particular, for bulletproof vests, combat helmets, personal body armor and/or for shielding light infantry and passenger automobiles.

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