Analysis of Vehicle Frame of SCX 3.5 Generation

Import 02/11/2016Tato diplomová práce se zabývá návrhem, optimalizací a analýzou rámu vozu SCX 3.5 generace. Návrh vychází ze současného vozu SCX 3 generace. Úpravy proběhnou v takovém měřítku, aby vyhovoval potřebám pro následnou generaci automobilu. Výpočtová analýza se bude skládat ze tří částí, jedná se o modální analýzu, torzní tuhost a pevnostní analýzu při jednotlivých jízdních režimech. Cílem této práce je navrhnout a upravit rám tak aby obstál ve všech kritériích, které jednotlivé zkoušky nastavují, a zároveň vyhověl zástavbovému prostoru. Jednotlivé analýzy jsou vypočteny numericky a to metodou konečných prvků (MKP), za pomoci softwaru Patran / Nastran 2014.1.This thesis deals with the design, optimization and analysis of the Generation SCX 3.5 car frame. The proposal builds on the current Generation SCX 3 car. The proposed adjustments are of such extent as to meet the needs of the next car generation. The computational analysis consists of three parts - modal analysis, torsional rigidity and strength analysis in various driving modes The aim of this thesis is to design and customize the frame in such manner that it meets all the criteria set by the individual tests as well as the inner space. Individual analyses are calculated numerically using the finite elements method (FEM) and software Patran / Nastran 2014.1.330 - Katedra aplikované mechanikyvýborn

HEAT TRANSFER MODELLING OF TWO-PHASE FLOW IN ISOLATED CHANNEL

This paper deals with Post-CHF (critical heat flux) heat transfer with the focus on different regimes of film boiling. The new thermal-hydraulic code TUBE 2.0 is presented. This code uses the equation of energy conservation and predefined correlations to establish wall temperature, the departure of nucleate boiling ratio as well as other parameters of cooling in a simple geometry - an isolated channel. With experimental data of inverted annular film boiling from Stewart, the best-performing correlation for calculation of post-CHF heat transfer in the channel was determined. Finally, the new presented code TUBE 2.0 and subchannel code SUBCAL owned by Chemcomex a.s. are compared using results of various experiments conducted by Becker. Data from Stewart could not be used because of inability to predict the onset of boiling crisis with several correlations

Application of Laser Sensor Q100 for 3D Strain Measurement

Import 05/08/2014Tato bakalářská práce se zaměřuje na přesnost a použitelnost optického tenzometru Dantec Dynamics Q100 v praxi. Pro verifikaci přesnosti metody ESPI byl realizován kvazistatický test na duralovém vzorku při čtyřbodovém ohybu na přístroji TESTOMETRIC 500-50CT. Výsledky experimentu byly srovnány s výsledky analytického a numerického vypočtu. Pro numerickou analýzu byla zvolena metoda konečných prvků (MKP), která byla provedena v programu ANSYS 15. Poznatky z uvedené studie umožnily vyhodnocení dvou praktických úloh. První řešenou úlohou bylo stanovení kontur přetvoření u kompozitu namáhaného na smyk, druhým případem pak experimentální analýza napětí na pantu průmyslové pračky. Závěrem jsou formulovány výhody přístroje a nejpodstatnější omezení pro jeho použití.The Bachelor´s thesis is focused on accuracy and applicability of the optical strain gauge Dantec Dynamics Q100 in practice. To verify accuracy of the method ESPI was realized quasi-static test on duralumin sample during four-point bend on TESTOMETRIC 500-50CT device. Results of experiment were compared with results of analytic and numeric evaluation. For numeric analysis was chosen method of finite elements (MKP) which was done in software ANSYS 15. Findings of mentioned study allowed the evaluation of two practical problems. First solved problem was determine the role of contour deformation of composites loaded in shear, second one was experimental analysis of tension on hinge of industry washing machine. At the end are formulated advantages of device and the most important restrictions for its use.339 - Katedra pružnosti a pevnostivýborn

RESIDUAL HEAT POWER REMOVAL FROM SPENT NUCLEAR FUEL DURING DRY AND WET STORAGE

This project deals with the thermal analyses of the wet and dry storages of the spent nuclear fuel. The dry spent fuel storage sub-channel code COBRA-SFS has been used in order to calculate the temperature field. In this code, the new model of residual heat removal was created for the SKODA 1000/19 cask where the spent nuclear fuel TVSA-T type from NPP Temelin will be stored. The object of calculations was to obtain the inside temperatures under maximum loads. After that, the results were compared to the requirements of the local regulatory body. Because of the absence of experimental data, the validation of the created computational models could not be accomplished. However, according to the verification scheme of the COBRA-SFS authors, the verification of the new models was implemented

Spontaneous charge carrier localization in extended one-dimensional systems

Charge carrier localization in extended atomic systems has been described previously as being driven by disorder, point defects or distortions of the ionic lattice. Here we show for the first time by means of first-principles computations that charge carriers can spontaneously localize due to a purely electronic effect in otherwise perfectly ordered structures. Optimally-tuned range-separated density functional theory and many-body perturbation calculations within the GW approximation reveal that in trans-polyacetylene and polythiophene the hole density localizes on a length scale of several nanometers. This is due to exchange-induced translational symmetry breaking of the charge density. Ionization potentials, optical absorption peaks, excitonic binding energies and the optimally-tuned range parameter itself all become independent of polymer length as it exceeds the critical localization scale. Moreover, lattice disorder and the formation of a polaron result from the charge localization in contrast to the traditional view that lattice distortions precede charge localization. Our results can explain experimental findings that polarons in conjugated polymers form instantaneously after exposure to ultrafast light pulses.Comment: 5 pages, 4 figure

INVESTIGATION OF CRITICAL HEAT FLUX ON ABRADED INCONEL 625 TUBE

Aim of this work was to study flow boiling in an annular channel at low pressure and low flow on a tube with modified surface roughness. The tube with the outer diameter of 9.14 mm and the heated length of 380 mm was made of Inconel 625 and was manually modified using 150 grit sandpaper. The tube was placed in a glass tube with an inner diameter of 14.8 mm. Outlet pressure was set to 120, 200 and 300 kPa with varying mass flow from 400 to 600 kg/(m2.s). A high speed camera was used to record several experiments to fully understand ongoing phenomena. Surface roughness was analysed using a confocal laser microscope and the effects of different mass flux and pressure on the CHF value were observed. Above all, the optimization of the flow parameters was done from the collected data and from the observed behaviour of the experimental loop

EXPERIMENTAL INVESTIGATION OF CRITICAL HEAT FLUX IN ANNULUS AT LOW PRESSURE AND LOW FLOW PARAMETERS

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, 600 and 1000 kg/(m2.s) mass flow. Water of these parameters was entering into the vertically aligned annulus, where the uniformly heated tube was placed until the critical heat flux (CHF) appeared. The experimental data were compared to estimations of CHF by local PGT tube correlation and Groeneveld’s look-up tables for tubes. The results imply that in the region of low pressure and low mass flux, the differences between calculations and experiments are substantial (more than 50 % of CHF). The calculations further imply that look-up tables and tube correlations should be corrected to the annulus geometry. Here, the Doerffer’s approach was chosen and led to a substantial enhancement of CHF estimation. Yet, a new correlation for the region of low pressure and flow is needed