Národní úložiště šedé literatury Nalezeno 55 záznamů.  začátekpředchozí27 - 36dalšíkonec  přejít na záznam: Hledání trvalo 0.01 vteřin. 
Experimentální stanovení creepových vlastností a chování při uniaxiálním namáhání materiálu C/PPS vyrobeného z pelet
Kytýř, Daniel ; Fíla, Tomáš ; Šleichrt, Jan ; Fenclová, Nela
Primárním úkolem zprávy je popis creepového chování sady vzorků vyrobených z peletek po inovaci výrobní technologie. Pro měření deformací byla použita primárně bezkontaktní optická metoda doplněna lokální tenzometrií. Pro popis creepového chování vzorků byl použit Findleyho model.
Experimental study of tile grout material behavior
Kumpová, Ivana ; Kloiber, Michal ; Ševčík, Radek ; Kytýř, Daniel
Study provides preliminary results of experimental study of tile grout material behavior. Experiments were performed with the use of microCT, three point bending test and methods for chemical analysis. It was proven that material behave very elastic and the suitability of the combination of used methods.
On the X-ray micro-tomography measurements of biological samples under compressive loading
Fíla, T. ; Kumpová, Ivana ; Zlámal, Petr ; Kytýř, Daniel ; Koudelka_ml., Petr ; Doktor, Tomáš ; Jiroušek, Ondřej
In this paper, compact loading device for micro-CT measurements under applied load was used in a series of instrumented compressive test of bone sample. Tested bone samples were loaded in several deformation steps and micro-CT scanning was carried out in each step. Reconstructed three-dimensional data of intact bone sample were used to develop 3D model of the specimen. Data from each deformation step were processed by DVC method for identification of displacement and strain fields and thus for evaluation of deformation response of human trabecular bone sample.
Calibration of an image processing tool for analysis of fibre orientation in fibre reinforced composites
Hos, J. ; Doktor, T. ; Petráňová, Veronika ; Kytýř, Daniel
This paper deals with calculation of fibre orientation distribution (FOD) in fibre reinforced composite. The calculation was based on image analysis algorithm applied on image acquired by scanning electron microscope. A composite with oriented fibres was selected to be enable calibration of the algorithm by comparison of the obtained results with FOD declared by the manufacturer.
Assessment of damage propagation in carbon-fibre composite under cyclic loading
Šleichrt, J. ; Fíla, T. ; Šperl, Martin ; Kytýř, Daniel
Carbon-fibre composite is very popular material in aircraft industry. Application of this material is limited by low fragility and low impact resistance. In flight airplane can be initialy damaged by hailstorm or bird strikes. Vibrations of the engine and turbulence during flight may cause propagation of this damage. This study describes the of laser profilometry to investigate post damage under cycling loading.
Proceedings of 13th Youth symposium on experimental solid mechanics
Kytýř, Daniel ; Zlámal, Petr ; Růžička, M.
Proceedings of the 13th Youth Symposium on Experimental Solid Mechanics held in Decin, Czech Republic. The symposium is focused on experimental methods and numerical simulation in engineering sciences. The proceedings capture the trends in development of experimental methods in mechanics of structures and materials (regardless to the material and structure type, covering fields from civil and mechanical engineering to biomechanics) as well as deployment of particular solution for measurement and automation systems for evaluation of experimental data.
Experimental study on size effect in quasi-static compressive behavior of closed-cell aluminium foams
Koudelka_ml., Petr ; Zlámal, Petr ; Kytýř, Daniel ; Fíla, Tomáš ; Jiroušek, Ondřej
The size effect in compressive deformation behaviour of commercially available aluminium closed-cell foam Alporas was studied under quasi-static loading conditions with different boundary conditions. Dimensions of the specimen’s cross-section were selected to match those of sufficient representative volume element (RVE) obtained by spectral analysis of the macroscopic structure whereas different heights of specimens were tested to examine size-scaling factor. Mechanical properties were derived from three different data sources: I) using data captured by load-cell, II) by digital image correlation (DIC) of displacement of contact faces, III) by DIC of the specimen’s structure. Mechanical testing was performed in custom-built loading device as well as in Instron 4301 electromechanical testing system with custom computer control software.
Investigation of composite material degradation indicators using acoustic measurement: comparison with laser vibrometry
Fíla, Tomáš ; Urushadze, Shota ; Kytýř, Daniel ; Valach, Jaroslav ; Šperl, Martin
This paper deals with investigation of acoustic material degradation indicator (attenuation decrement drop of selected natural frequency) measured by a custom-built experimental device. Samples of C/PPS fibre composite material were analyzed. Acoustic signals were recorded and processed using spectral analysis and sound signal regression. Data measured by this method were verified by comparative experiment. Specimens were simultaneously measured using both acoustic experimental device and laser vibrometer. Modal analysis of the specimen were carried out prior to the experiment. This enabled assessment of specimens natural modes and therefore the best impact zone. In total, 10 measurements were performed for each specimen at the same level of degradation. Measured data were then processed and compared. The specimens were repetitively measured after designated number of loading cycles.
Design and use of novel compression device for microtomography under applied load
Fíla, Tomáš ; Zlámal, Petr ; Koudelka_ml., Petr ; Jiroušek, Ondřej ; Doktor, Tomáš ; Kytýř, Daniel
This paper deals with modification and usage of custom-designed compression device, that allows real time X-ray tomography scanning of specimen under applied pressure. In this case microtomography is used to obtain data required to determine specimens morphology and to develop 3D material model (especially for cellular materials such as bones, metal foams and quasi-brittle materials or particle composites such as concrete or cementitious composites). Important design changes were made in the existing device frame to increase its load capabilities, stiffness and to accomodate a larger specimen. Finally device displacement measurements were conducted and calibration experiment was carried out.
Indirect determination of material model parameters for single trabecula based on nanoindentation and three-point bending test
Zlámal, P. ; Jiroušek, Ondřej ; Kytýř, Daniel ; Doktor, Tomáš
The aim of the paper is to develop a procedure for determination of elasto-visco-plastic constitutive model with damage for human single trabecula. The procedure is suited for indirect establishing of material model based on nanoindentation and three-point bending test. Constants of the material model are identified by Finite Element (FE) simulations and curve fitting using an algorithm based on least squares fitting of the experimental curves. In the case of nanoindentation, the penetration depth of tip during the FE analyses (FEA) is fitted to experimental nanoindentation curves. In the case of three-point bending, displacements of nodes are compared with displacements of markers observed during the experiment using digital image correlation.

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