Národní úložiště šedé literatury Nalezeno 12 záznamů.  1 - 10další  přejít na záznam: Hledání trvalo 0.00 vteřin. 
Book of Abstracts. 18th Youth Symposium on Experimental Solid Mechanics
Kytýř, Daniel ; Doktor, Tomáš ; Zlámal, Petr
The YSESM symposium provides a forum for young researchers and engineers, PhD students and students dealing with subjects of experimental mechanics. The Symposium concentrates on current work in all areas of experimental research and its application in solid and fluid mechanics. The topic will particularly concern to: Conventional and Advanced Experimental Methods in Solid and Fluid Mechanics; Non-Destructive Testing and Inspection, Measurements in Material Science, Computer Assisted Testing and Simulation, Engineering Design Simulation, Hybrid Methods, Experimental Techniques – Numerical Simulation, Optical Methods and Image Processing, Measurements in Biomechanics, Sensor Techniques for Micro- and Nano-Applications, Measurement Methods for Forensic Engineering.
Book of abstracts. XVIIth Youth symposium on experimental solid mechanics
Kytýř, Daniel ; Doktor, Tomáš ; Zlámal, Petr
The YSESM symposium provides a forum for young researchers and engineers, PhD students and students dealing with subjects of experimental mechanics. The Symposium concentrates on current work in all areas of experimental research and its application in solid and fluid mechanics.
Acta Polytechnica CTU Proceedings
Kytýř, Daniel ; Major, Z. ; Doktor, Tomáš
The 16th symposium continues both the long tradition of this conference series and introduces novel elements. The YSESM 2018 symposium provides a forum for young researchers and engineers, students and PhD students dealing with subjects of experimental mechanics. In addition, the combination of the experimental mechanics with modern numerical methods will be a new focus of this 16th Symposium.
Influence of printing and loading direction on mechanical response in 3D printed models of human trabecular bone
Doktor, Tomáš ; Kumpová, Ivana ; Wroński, S. ; Śniechowski, M. ; Tarasiuk, J. ; Forte, G. ; Kytýř, Daniel
The paper deals with investigation on directional variations of mechanical response in 3D printed models of human trabecular bone. Sample of trabecular bone tissue was resected from human donor and 3D model was obtained by X-ray computed tomography. Then a series of cubical samples was prepared by additive manufacturing technique and tested by uniaxial compression loading mode. Mechanical response was compared in nine different combinations of direction of 3D printing and loading direction. The results show neglectible influence on the deformation response in elastic region (stiffness) and significant changes of the behaviour in plastic region (stress and strain at yield point, strain at full collapse).
Utilization of image and signal processing techniques for assessment of built heritage condition
Koudelka_ml., Petr ; Koudelková, Veronika ; Doktor, Tomáš ; Kumpová, Ivana ; Kytýř, Daniel ; Valach, Jaroslav
Historical buildings represent invaluable heritage from the past and therefore their protection is a very important task. Assessment of their condition must not cause damage accumulation thus the least possible volume removed from the structure is essential. As many historical buildings in the Czech Republic are built using sandstone that can be considered as a typical heterogeneous system, statistical signal processing is a promising approach for determination of the representative volume element (RVE) dimensions. Such calculations can be carried out on the domain of logical arrays representing binary images of the materials microstructure. This paper deals with processing of image data obtained using SEM-BSE and high resolution flatbed scanner for determination of RVE dimensions. Advanced image processing techniques are employed and results from calculation using grayscale data are presented and compared with results calculated on the basis of color input images.
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.
Comparative study on numerical and analytical assessment of elastic properties of metal foams
Koudelka_ml., Petr ; Jiroušek, Ondřej ; Doktor, Tomáš ; Zlámal, Petr ; Fíla, Tomáš
Recently, titanium metal foams are being considered as a suitable replacement for substituting trabecular bone microstructure especially for their similar pore distribution. The most common methods for determination of compressive effective elastic properties of such materials involve different approaches based on finite element analysis (FEA) of their microstructure. The internal geometry is usually modeled by two different methods - directly on the basis of a series of CT scans or using one of discretization schemes. However, all these techniques require highly specialized hardware, software and significant amount of computational time. In this paper, the effective elastic properties of the metal foam are instead obtained by analytical modulus-porosity relations and results are compared with previous FE based analysis.
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.
Early Defect Detection of Acetabular Implants
Kytýř, Daniel ; Jiroušek, Ondřej ; Zlámal, Petr ; Doktor, Tomáš ; Jandejsek, I.
The paper is focused on possibilities of modern X-ray detectors and micro-focus X-ray source for investigation of early degradation processes of acetabular implants. To simulate the most adverse activity (downstairs walking) a hip joint simulator was developed. The experimental setup was designed for cyclic loading of polyethylene acetabular cup implanted into the human pelvic bone and fixed by commercial polymethyl methacrylate bone cement. To predict the bone degradation numerical analysis of detailed three-dimensional model of the acetabular cup and the cement mantle implanted in a bone block was performed. Using large area flat panel detector and microfocus X-ray source it is possible to investigate micro-damage propagation and detect early defect in the bone-implant interface.

Národní úložiště šedé literatury : Nalezeno 12 záznamů.   1 - 10další  přejít na záznam:
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