National Repository of Grey Literature 9 records found  Search took 0.00 seconds. 
Possibilities of using 4D computed tomography in fracture tests
Kumpová, Ivana ; Fíla, Tomáš ; Koudelka, Petr ; Rozsypalová, I. ; Keršner, Z. ; Kytýř, Daniel ; Vopálenský, Michal ; Vavřík, Daniel ; Vyhlídal, M. ; Drdácký, Miloš
The paper presents the study of the internal structure and fracture properties of selected quasi-brittle building materials subjected to temperature changes and the possibility of applying the method combining bending fracture tests and time-dependent computed tomography (4D CT). The tested specimens were subjected to hightemperature effects and subsequently tested by a four-point bending during 4D CT. Thus, 3D image information was obtained in different phases of loading and material damage. Comparative compression strength measurements were also performed. These results are in good agreement
Basic features of aggregate-matrix-interface fracture of concrete: pilot modelling
Vyhlídal, M. ; Šimonová, H. ; Veselý, V. ; Keršner, Z. ; Klusák, Jan ; Malíková, Lucie
In this paper, the attention is paid to investigation of the importance of the Interfacial Transition Zone (ITZ) in concrete for the global fracture behaviour. A simplified cracked geometry (consisting matrix, ITZ and aggregate) is modelled by means of the finite element method with a crack terminating at the matrix-ITZ interface. Numerical studies assuming two various ITZ thicknesses and several various ITZ elastic moduli are performed. Based on the values of the opening stress ahead of the crack tip (its average value and stress range) a few conclusions are discussed. The pilot analyses dealing with the effect of ITZ on the stress distribution should contribute to better description of toughening mechanisms in silicate-based composites.
Fracture of selected building composites in the vicinity of aggregate-matrix-interface
Vyhlídal, Michal ; Malíková, Lucie (referee) ; Keršner, Zbyněk (advisor)
The interface between aggregate grains and matrix in cementitious composites is their weakest element. The topic is particularly significant in the case of high performance and high strength concrete technology for which the eliminination or reduction of these weak links are necessary. The aim of this thesis is to determine the influence of the interface on the fracture behaviour of the cementitious composites. The fracture experiments were performed for this purpose and were complemented by the nanoindentation’s results and scanning electron microscopy results. Numerical model was created in ANSYS software on the basis of these data and the fracture toughness values of the interface were evaluated by means of the generalized fracture mechanics principles. Conclusion of the thesis is proof that the interface properties have a significant influence on the fracture behaviour of cementitious composites.
Basic features of aggregate-matrix-interface fracture of selected building composites
Vyhlídal, Michal ; Seitl, Stanislav (referee) ; Keršner, Zbyněk (advisor)
The aim of this work is to analyze the behavior of cement composite, depending on the features of ITZ. The first part of the thesis is theoretical and deals with the origin and features of ITZ, defines the basic relationships and concepts of continuum mechanics and linear elastic fracture mechanics and presents crack tips posibilities in the three-phase composite, including their short characterization. The second part is practical and describes creation of numerical model in the ANSYS software, presentation of partial results and compare of them. The result of this work is a comparison of the mean values of stress and amplitude of stress depending on the features of ITZ.
Strategy Competitive Fight
Vyhlídal, Martin ; MBA, Stanislav Heža, (referee) ; Bartes, František (advisor)
The thesis deals with finding such a competitive strategy, which enables a well-established Copany to remain on the leading edge of sales finance market in the Czech Republic. To do that, it is necessary to acquire as detailed information about competitors´ activities, professional environment development and end-user preferences trend, as possible. Based on this information it proposes possible models of strategic options including the impact on customers, business partners and internal issues.
Vliv stupně zakmenění na faunu nočních motýlů
Vyhlídal, Martin
This thesis deals with a investigation of the forest night night Lepidoptera. There is in introduction a review about problemacy of coppiced and coppiced forests with standards in the relation to the day and night active Lepidoptera species. There are also presented research localities of the project TARMAG and there are introduced wider spatial relations. My particular research was done on these localities, which are under management of the project TARMAG together with ŠLP Masarykův les Křtiny. The management is like coppiced forest with standards volume of tree stands is between 4--10. During the years 2012 and 2013 I collected 8 times on each locality by using light traps, totally I collected 24 times altogether. There were collected 152 species (151 specimens of night Lepidoptera which belong to 10 families. From point of view of absolute numbers, the higher proportion of species was found in not managed stand forest, then in coppiced one. The question is, if it was due to lack of management or due other factors.

See also: similar author names
1 Vyhlídal, M.
3 Vyhlídal, Martin
4 Vyhlídal, Michal