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X-RAY computer tomography in geotechnics
Blaheta, Radim; Kohut, Roman; Kolcun, Alexej; Souček, Kamil; Staš, Lubomír
2011 - anglický
The paper describes some experience with the X-ray CT-FEM analysis. It focuses on geocomposites arising by chemical grouting of coal substances and on using mathematical modelling of response to a load. The application potential of this new methodology is found in utilization of obtained properties for solving the stability problems by numerical modelling of geotechnical projects.
Klíčová slova:
X-ray CT; geocomposite; FEM; homogenization
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
X-RAY computer tomography in geotechnics
The paper describes some experience with the X-ray CT-FEM analysis. It focuses on geocomposites arising by chemical grouting of coal substances and on using mathematical modelling of response to a ...
Study of surface topography generated by the action of pulsating water jet
Klich, Jiří; Valíček, Jan; Sitek, Libor; Foldyna, Josef; Harničárová, M.; Hlaváček, Petr
2011 - anglický
The paper is dealing with study of the surface topography created by the pulsating water jet. Topography is evaluated by height characteristics of the surface roughness (average roughness Ra and average maximum height of the profile Rz). The data obtained from surface texture are analyzed and interpreted in relation to the stand-off distance between the nozzle and the surface.
Klíčová slova:
pulsating water jet; surface roughness; surface topography
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Study of surface topography generated by the action of pulsating water jet
The paper is dealing with study of the surface topography created by the pulsating water jet. Topography is evaluated by height characteristics of the surface roughness (average roughness Ra and ...
Forces and Moments in CFD Analysis
Říha, Zdeněk; Foldyna, Josef
2010 - anglický
The paper shows how to find the force point of action, when we know the total force and the total moment. It is usual case if we solve fluid flow with help of a CFD code. Correct interpretation of force´s act is very important for next possible analysis.
Klíčová slova:
force; CFD analysis; CFD code
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Forces and Moments in CFD Analysis
The paper shows how to find the force point of action, when we know the total force and the total moment. It is usual case if we solve fluid flow with help of a CFD code. Correct interpretation of ...
Hummock Grasses on the Mt. Keprník: Contribution to the Earth Hummocks Origin Discussion
Hrádek, Mojmír
2010 - anglický
Proofs submitted hitherto in evidence of earth hummocks cryogenic origin have been found as little probative. In presented poster, the attention was focused on the role of vegetation in hummocks origin. Some of hummocks are formed by dominant grass tussock with special habitus. Hummock grasses in the genus Carex sp., Eriophorium sp., resp. Juncus trifidi and Deschampsia sp. grow as an expanding dome, with green leaves in the centre and dead leaves at outer margin. Layer of dry leaves may be up to 5 cm thick and can serve as heat-insulation layer protecting frozen ground thawing in spring-time. Similar grass hummocks are typical not only for wind-swept alpine grasslands but also for low ranges and plains.
Klíčová slova:
Hrubý Jeseník Mts.; earth hummocks; hummock grasses
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Hummock Grasses on the Mt. Keprník: Contribution to the Earth Hummocks Origin Discussion
Proofs submitted hitherto in evidence of earth hummocks cryogenic origin have been found as little probative. In presented poster, the attention was focused on the role of vegetation in hummocks ...
Fracture toughness of rocks and influence of the loading velocity in mode I
Vavro, Leona
2010 - anglický
The presented paper presents another results of the rocks fracture toughness measurement. The influence of the loading velocity on the fracture parameters was investigated. The loading velocity was continually changed in values 1; 0,1 a 0,01 mm/s. The measurements were realized on selected rocks in the laboratory conditions in the Institute of Geonics AS CR.
Klíčová slova:
fracture toughness; rock; extensometer; damage process
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Fracture toughness of rocks and influence of the loading velocity in mode I
The presented paper presents another results of the rocks fracture toughness measurement. The influence of the loading velocity on the fracture parameters was investigated. The loading velocity was ...
Probabilistic designing of bolted support
Janas, P.; Krejsa, M.; Šňupárek, Richard; Krejsa, V.
2010 - anglický
The paper briefly reviews one of the proposed methods of probabilistic reliability assessment of anchoring reinforcement usable in mine excavations and undergroundworkings. Application of this koncept – software „Kotvení“ (Anchoring) was especiallydeveloped for this purpose usingDirect Determined Fully Probabilistic Method (DDFPMB).
Klíčová slova:
bolting; probabilistic design; anchoring reinforcement
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Probabilistic designing of bolted support
The paper briefly reviews one of the proposed methods of probabilistic reliability assessment of anchoring reinforcement usable in mine excavations and undergroundworkings. Application of this koncept ...
Bending of Beam with Free Ends on Non-linear Subsoil
Sysala, Stanislav
2010 - anglický
A semi-coercive problem with a beam on a unilateral elastic subsoil of Winkler type is investigated in the contribution. Firstly, the existence, the uniqueness and the continuous dependence on data of the problem solution are discussed. Secondly, the problem is approximated by the finite element method, where the subsoil is replaced by insulated "springs" due to a numerical quadrature. The relations between the original problem and the family of approximated problems are introduced. Thirdly, suitable numerical methods of Newton type are introduced. The convergence analysis of the methods is investigated. The dependence of the methods on the discretization parameter and the load is also discussed. And finally, some of the theoretical results are illustrated on numerical examples.
Klíčová slova:
beam on subsoil; non-linearity; semi-coercivity
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Bending of Beam with Free Ends on Non-linear Subsoil
A semi-coercive problem with a beam on a unilateral elastic subsoil of Winkler type is investigated in the contribution. Firstly, the existence, the uniqueness and the continuous dependence on data of ...
Seismic Loading of Underground Bridge above Medieval Mine
Knejzlík, Jaromír; Lednická, Markéta; Kaláb, Z.
2010 - anglický
Problems with high seismic load in the medieval Jeroným mine working were generated also by heavy trucks on the road above the mine. Because damages of road occurred above the near shallow mine spaces, the road was supported by underground bridge. This paper describes experimental seismic measurements that was targeted the traffic loading of underground spaces.
Klíčová slova:
seismological measurement; seismic loading; medieval mine
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Seismic Loading of Underground Bridge above Medieval Mine
Problems with high seismic load in the medieval Jeroným mine working were generated also by heavy trucks on the road above the mine. Because damages of road occurred above the near shallow mine ...
On the worst scenario method: Application to uncertain nonlinear differential equations with numerical examples
Harasim, Petr
2010 - anglický
In this contribution, the worst scenario method is applied to problem described by nonlinear differential equation with uncertain coefficients. Above all, some illustrative numerical examples including algorithm are presented.
Klíčová slova:
worst scenario method; nonlinear differential equations; numerical approximation
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
On the worst scenario method: Application to uncertain nonlinear differential equations with numerical examples
In this contribution, the worst scenario method is applied to problem described by nonlinear differential equation with uncertain coefficients. Above all, some illustrative numerical examples ...
Multiscale modelling of geomatrials and iterative solvers
Blaheta, Radim; Byczanski, Petr; Harasim, Petr
2009 - anglický
The knowledge of microstructure in combination with properties of the constituents and mathematical modelling can be used for investigation of the properties of geomaterials at application scale. We investigate problems with both deterministic knowledge of microstructure, derived from X-ray CT scans, and stochastic one. The stochastic generation is also used for a systematic study of robustness of iterative solvers, particularly for Schwarz methods for PDE problems discretized by mixed FEM. Znalost mikrostruktury v kombinaci se znalostí vlastností složek a matematickým modelováním mohou být použity pro zkoumání vlastností geomateriálů v aplikačním měřítku. V článku se studuje řešení problémů s jak deterministickou znalostí mikrostruktury, odvozenou z RTG CT tomografie, a stochasticky určenou mikrostrukturou. Stochastická generace je také využita pro systematické studium robustnosti iterativních řešičů, zejména pokud jde o Schwarzovy metody pro PDR úlohy diskretizované smíšenou metodou konečných prvků.
Klíčová slova:
Multiscale modelling; iterative methods; mixed FEM
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Multiscale modelling of geomatrials and iterative solvers
The knowledge of microstructure in combination with properties of the constituents and mathematical modelling can be used for investigation of the properties of geomaterials at application scale. We ...
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