Prohlížení Acta Polytechnica CTU Proceedings. 2020 ( vol. 26-28) dle názvu
Zobrazují se záznamy 11-30 z 63
-
DESIGN OF TUNED MASS DAMPERS FOR LARGE STRUCTURES USING MODAL ANALYSIS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Tuned mass damper is a device, which can be highly useful when dealing with excessive vibration and is widely used in many engineering fields. However, its proper design and optimization is a complicated task. This study ... -
DIAGNOSTICS OF UNFIRED EARTH WITH METHYLENE BLUE TEST
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Unfired earth is important historic building material. Final properties of unfired earth constructions are influenced by amount and kind of clay in earth mixtures. Methylene blue test is a method that helps determining the ... -
DISTRIBUTION OF HYDRATION PRODUCTS IN THE MICROSTRUCTURE OF CEMENT PASTES
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)This case study focuses on the quantification of the amorphous hydrate distribution in the microstructure of hardened cement paste. Microtomographic scans of the hardenend cement paste were thresholded based on histogram ... -
DYNAMIC IMPACT WEAR AND IMPACT RESISTANCE OF W-B-C COATINGS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Coated components used in industry are often exposed to repetitive dynamic impact load. The dynamic impact test is a suitable method for the study of thin protective coatings under such conditions. Aim of this paper is to ... -
ELECTRON RADIATION EFFECT ON INDENTATION CREEP OF CONSTRUCTION POLYMERS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Cross-linking is a process in which polymer chains are associated through chemical bonds. Radiation, which penetrated through specimens and reacted with the cross-linking agent, gradually formed cross-linking (3D net), ... -
ESTIMATION OF ANISOTROPIC ELASTIC PROPERTIES OF CARBON FIBERS USING NANOINDENTATION
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Understanding the mechanical behavior of carbon fiber reinforced polymers requires knowledge on the deformation behavior of carbon fibers, they are highly anisotropic and heterogeneous. Nanoindentation is an efficient ... -
EULER AND EXPONENTIAL ALGORITHM IN VISCOELASTIC ANALYSES OF LAMINATED GLASS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Laminated glass combines two remarkable materials: glass and a polymer ply. While glass is stiff and brittle, the polymer ply is a rate-dependent compliant material. Together, they form a material which keeps the aesthetic ... -
EVALUATION OF INTERNAL COHESION OF MULTIPHASE PLASMA-SPRAYED COATINGS BY CAVITATION TEST: FEASIBILITY STUDY
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Mechanical characterization of plasma-sprayed coatings at microscopic level represents a major challenge due to the presence of numerous inherent microstructural features such as cracks, pores, or splat boundaries, which ... -
EXPERIMENTAL AND NUMERICAL INVESTIGATION OF CEMENT PASTE MICROSTRUCTURE AND ITS HYDRATION UNDER SHORT-TERM EXPOSURE TO ACETONE
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)The solvent exchange methods are commonly used in order to arrest cement hydration reaction. This paper presents preliminary results of experimental investigation of cement paste microstructure under short-term (24 hours) ... -
EXPERIMENTAL INVESTIGATION OF CRITICAL HEAT FLUX IN ANNULUS AT LOW PRESSURE AND LOW FLOW PARAMETERS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Steady state flow boiling experiments were conducted on a technically smooth Inconel 625 tube with outer diameter 9.1 mm at inlet pressures 131, 220 and 323 kPa, inlet temperatures 62, 78 and 94 °C and approximately 400, ... -
EXPERIMENTAL STUDY OF DAMAGED CR-COATED FUEL CLADDING IN POST-ACCIDENT CONDITIONS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)To enhance the safety of nuclear power, the focus of researchers all around the world has recently mainly objected on the development of Accident Tolerant Fuels. Especially the Chromium coating of current Zirconium based ... -
FRACTURE BEHAVIOR OF FeAlSi INTERMETALLICS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)The study is devoted to the intermetallic alloy FeAl20Si20 (wt.%) with the potential applications in high temperature aggressive environments. The samples of the same chemical composition were prepared by spark plasma ... -
HARDNESS OF HYBRID PVD-PECVD W-C:H COATINGS VS. SUBSTRATE TYPE
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)The effects of substrate on the measurement of hardness (and indentation modulus) - penetration depth profiles were investigated on hybrid PVD-PECVD W-C:H coatings made with the additions of C2H2 or CH4 using High Power ... -
HARDNESS OF NITRIDED LAYERS TREATED BY PLASMA NITRIDING
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Stainless steels, particularly the austenitic stainless grades are widely used in many industries due to good corrosion resistance, but very poor mechanical properties as surface hardness and wear resistance limit its ... -
HIGH-TEMPERATURE OXIDATION OF CHROME-NICKEL ALLOY
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)The investigations in this paper deal with the Cr-Ni alloy. The material has been recently proposed as a potential ATF concept, primarily due to its behaviour under high-temperature oxidation. A set of experiments to ... -
HOMOGENIZATION OF UNREINFORCED OLD MASONRY WALL COMPARISON OF SCALAR ISOTROPIC AND ORTHOTROPIC DAMAGE MODELS
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)Masonry is a heterogeneous composite material made of bricks bonded by a mortar matrix. Modeling such a material on macroscale typically calls for homogenization adopting a suitable constitutive model capable of capturing ... -
HOT HARDNESS MEASUREMENTS ON MATERIALS UP TO 600 °C DURING THE FIRST HOUR OF USING
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)In the aeronautical field, materials are used in severe environmental conditions (temperature, atmosphere, exposure time ...), particularly for engine applications. In order to characterize the use of these materials in ... -
INDENTATION SIZE EFFECT IN HIGH PRESSURE TORSION PROCESSED HIGH ENTROPY ALLOY
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)High entropy alloy HfNbTaTiZr in as cast conditions and after high pressure torsion straining was characterized by nanoindentation. The length-scale dependent material response (indentation size effect) was characterized ... -
INFLUENCE OF MATERIAL DAMPING ON THE RESPONSE OF UNDERGROUND STRUCTURES SUBJECTED TO EARTHQUAKE
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)The paper describes a finite element simulation of the response of a real underground structure subjected to earthquake using GEO5 FEM program. It concentrates on the influence of material damping with respect to a specific ... -
INFLUENCING THE INDENTATION CURVES BY THE BLUNTNESS OF THE BERKOVICH INDENTER AT THE FEM MODELLING
(České vysoké učení technické v PrazeCzech Technical University in Prague, 2020)The influence of the Berkovich indenter bluntness on the indentation curves at nanoindentation test of fused silica is determined by the FEM (finite element method) in this paper. The Berkovich indenter, which is mostly ...