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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
301

Framtagning av spännviddstabell för ribbdäcksbjälklag

Samsvik, Jonas, Norén, Adam January 2019 (has links)
Examensarbetets syfte är att finna en beräkningsgång för ribbdäcksbjälklag så att en spännviddstabell kan skapas. Ett ribbdäcksbjälklag består av stående limträbalkar med en liggande KL-träskiva ovan som fungerar som golv. I detta examenarbete är KL-träskivan 2,4 meter bred och vilar på två limträbalkar. Full samverkan mellan de olika materialen råder. Idag finns det några aktörer på marknaden som levererar liknande typer av bjälklag men det finns ingen beräkningsgång preciserad i Eurokod. Förstudien till examensarbetet har visat på att tillvägagångssättet för att lösa den mest problematiska beräkningen har varit densamma för de företagen vi har kollat på. Svårigheten är att beräkna den effektiva bredden för tvärsnittet. Det finns även olika standarder som gäller för hur stor nedböjningen får vara för ett bjälklag. I examensarbetet utförs beräkningar för att uppfylla de krav som gäller i Sverige samt de krav som gäller i Österrike. Detta görs för att dalamissivträ misstänker att kraven på de österrikiska bjälklagen är högre ställda med avseende på svikt, de vill kunna erbjuda ett styvare bjälklag. I tabellen ska dimensioner anges för att respektive krav ska uppfyllas. De österrikiska kraven har visat sig vara hårdare ställda jämfört med de svenska och kommer därför att kräva en balk av större dimension i de lägre lastfallen. I fallen med större laster kommer balkdimensionerna mellan de olika lastfallen inte att skilja sig. Där har det visast sig att branddimensioneringen varit helt dimensionerande. Tabellen ska vara ett hjälpmedel för företaget Dala massivträ att lättare nå ut till beställare. Beräkningsgången har gjorts i Mathcad, där okända parametrar har lösts ut och beräknats fram. Vissa parametrar har varit fasta utifrån Dala massivträs önskemål, så som KL-träskivans tjocklek och ingående komponenters materialegenskaper. När beräkningarna har gjorts har de kontrollerats så att momentkapacitet och tvärkraftskapacitet är tillräcklig i respektive last fall och spännvidd. Nedböjningen har kontrollerats liksom branddimensioneringen. Har bjälklaget inte uppfyllt hållfastighetsdimensionering eller kraven för svenskstandard alternativt österrikiskstandard har en högre dimension valts på limträbalken. Limträbalk har valts utifrån Setra trävarors standardsortiment. Resultatet av beräkningarna har förts in i en spännviddstabell som byggts upp för att enkelt kunna välja balk utifrån tänkt last fall. Beräknings exempel finns redovisat i en bilaga där ett lastfall och en spännvidd redovisas. Resultatet leder till att varje spännvidd och lastfall får två dimensioner, en för att klara svensk standard och en för att klara österrikiskstandard. I diskussionen diskuteras eventuella felkällor, effekten av tätare placering med limträbalkar och orsaken till en differens i jämförelsen mellan Mathcad och Calculatis. Även resultatet i spännviddstabellen diskuteras. / The purpose of the degree project is to find a calculation path for ribbed deck joists so that a span width table can be created. A ribbed deck joists consists of standing glulam beams with a lying cross laminated timber slab above which functions as a floor. In this thesis, the cross laminated timber board is 2.4 meters wide and rests on two glulam beams. Full cooperation between the different materials prevails. Today, there are some players in the market that deliver these types of floor but there is no calculation rate specified in Eurocode. The preliminary study for the degree project has shown that the approach to solving the most problematic calculation has been the same for the companies we have looked at. The difficulty is to calculate the effective width of the cross section. There are also different standards that apply to how large the deflection may be for a beam. In the thesis work, calculations are performed to meet the requirements that apply in Sweden and the requirements that apply in Austria. Dimensions must be specified in the table for fulfilling the respective requirements. The Austrian requirements have proved to be harder compared to the Swedish ones and will therefore require a beam of greater dimension in the lower load cases. In case with the larger loads, the beam dimensions between the different loads will not differ because it has been shown that the fire has been dimensional. The table should be a tool for the company Dala massivträ to reach the customer more easily. The calculation path has been made in Mathcad, where unknown parameters has been solved and calculated. Some parameters have been fixed based on Dala massivträ´s wishes, such as the thickness of the cross laminated timber board and the material properties of the component parts. Once the calculations have been made, they have been checked so that torque capacity and transverse power capacity are sufficient in the respective load cases and span. The deflection has been checked as well as the fire dimensioning. The flooring has not fulfilled the dimensioning or the requirements for Swedish standard alt. Austrian standard has a higher dimension selected on the glulam beam. Glulam beam has been selected based on Setra's wood products standard range. The result of the calculations has been entered into a span table which has been built up in order to be able to easily select the beam from outside the intended load case. The calculation example is presented in an annex where a load case and a span are reported. The result is that each span and load fall get two dimensions, one to meet the Swedish standard and one to cope with the Austrian standard. In the discussion, is discussed possible sources of error, the effect of denser placement with glulam beams and the cause of a difference in the comparison between Mathcad and Calculatis. The result in the span table is also discussed.
302

Analytický a syntetický přístup k řešení metrických úloh v prostoru / Analytic and synthetic approach to metrical tasks in space solving

Kreslová, Iva January 2019 (has links)
The diploma thesis deals with metric tasks in space, using synthetic and analytical geometry. In addition to explaining the different approaches, there is a set of examples to practice. The solution of the examples is part of the Portal of High School Mathematics (Portál středoškolské matematiky), where we can and analytical solutions, synthetic numerical solutions and synthetic constructional solutions.
303

AVALIAÇÃO DE FORÇAS LIBERADAS POR ALÇAS EM FORMA DE GOTA UTILIZADAS EM MECÂNICA ORTODÔNTICA PARA FECHAMENTO DE ESPAÇOS / EVALUATION OF FORCES DELIVERED BY TEARDROP LOOPS USED IN ORTHODONTIC MECHANICS FOR CLOSING SPACES

D'ornellas, Mauro Cordeiro 22 January 2010 (has links)
The purpose of this research was to investigate the influence of height, crosssection and metal alloy in the mechanical act of teardrop loops used in incisors retraction and in en masse retraction of incisors and canines, aiming analyze the mechanical behavior of these loops in relation to optimum forces presented in the literature. Two hundred and forty loops were submitted to a tensile load on the testing machine considered heights of 6mm, 8mm and 10mm; cross-sections of 0.018in.x 0.025in and 0.019in.x 0.025in and wire materials of stainless steel and beta-titanium alloys. It was obtained magnitudes of horizontal force (N) and load-deflection (N/mm) for each loop across activations of 0.5mm, 1mm, 1.5mm, 2mm and 2.5mm. The results showed that height (p<0.01), cross-section and metal alloy (p<0.05) were considered significant factors with reference to horizontal force and load-deflection. There was no influence of one factor but a combination of these trying to achieve very light forces. This study suggest that is necessary a large orthodontic biomechanics knowledge with respect to loops design used in incisors retraction and in en masse retraction of incisors and canines, selecting adequate height, crosssection and metal alloy. / O objetivo desta pesquisa foi investigar os efeitos da altura, secção transversal e tipo de liga no desempenho mecânico de alças confeccionadas em forma de gota, indicadas para a retração de incisivos e para a retração em massa de incisivos e caninos, buscando avaliar o comportamento das mesmas em relação às magnitudes de força ótima existentes na literatura. Foram submetidas a um ensaio mecânico 240 alças, considerando as alturas de 6mm, 8mm e 10mm; as seções transversais de 0.018 x 0.025 e de 0.019 x 0.025 e as ligas de aço inoxidável e beta-titânio (TMA). Foram obtidos valores de força horizontal (N) e carga-deflexão (N/mm) para cada alça mediante ativações de 0.5mm, 1mm, 1.5mm, 2mm e 2.5mm. Os resultados mostraram que a altura (p<0.01), a secção transversal e a liga (p<0.05) foram consideradas fatores significativos na força horizontal e cargadeflexão gerada. Não houve influência de um fator sobre os demais, mas sim, uma combinação destes, buscando atingir forças muito leves. Este estudo sugere que é necessário amplo conhecimento da biomecânica ortodôntica na confecção de alças direcionadas para a retração dos dentes anteriores, selecionando adequadamente a altura, a secção transversal e a liga.
304

Statické řešení rodinného domu / Static solution of family house

Formánek, Pavel January 2018 (has links)
Master´s thesis is divided into two parts. In first part is author focusing on designing load-bearing structures that are made of reinforced concrete (floor slab, external wall, stairway). The assessments of those structures were made according to valid standard of ČSN EN 1992-1-1 and structural part of design documentation to those constructions were processed. In second, theoretical, part are different models of reinforced concrete slab in 3D (as part of whole construction) and in 2D created. The main task was to compare influence of different support´s stiffness in models on internal forces (bending moments) and on deflection of slab.
305

Návrh železobetonového objektu s ohledem na požadavky požární odolnosti / Design of reinforced concrete structure with respect to fire resistance requirements

Pivodová, Alena January 2019 (has links)
The diploma thesis deals with an analysis of internal forces of B4 reinforced construction of an office building. Analysis takes into account interaction with subsoil and when designing structural parts of the building, different requirements for fire resistance of a structure are taken into account. A Dlubal RFEM 5.17 program was used for finite element analysis, and model functionality verification was performer by using a summation of moments method. The thesis deals with the design and assessment of a point-supported slab, column, inner and external walls.
306

Využití moderních kompozitních materiálů při návrhu betonových konstrukcí / The use of advanced composite materials for the design of concrete structures

Bártová, Denisa January 2020 (has links)
This diploma thesis deals with the design of FRP reinforced concrete structures. The theoretical part is focused mainly on the punching shear of a flat two way slab according to ACI, fib Bulletin, CSA, and JSCE standards. This thesis also includes a description of the punching shear resistance according to Eurocode 2. FRP reinforcement, its mechanical properties, and their behaviour in time are also described. Next, a parametric study was performed that examines the effects of various parameters on the punching shear resistance according to the standards mentioned above. At the end a non-linear analysis using the ATENA software was performed. The practical part includes a structural design of a flat two way slab. The slab uses a steel reinforcement at the bottom, while the top is reinforced with FRP reinforcement. The punching shear design is also included. In the last chapter the serviceability limit state is checked, specifically the slab long-term deflection. The thesis also includes drawings. All calculations were performed in accordance with Eurocode 2 and fib Bulletin No. 40.
307

Řešení statického zajištění přístavby stávajícího objektu / Structural strengthening of the outbuilding of existing construction

Pelouch, Adam January 2021 (has links)
Diploma thesis is focused on structural assessment and strengthening of the reinforced concrete flor slab disturbed by excessive deflection. Thesis included assesment of the existing construction and design method of strengthening of the floor structure with system using prestressing strands without bond.
308

Rekonstrukce budovy pivovaru s předpjatými stropními deskami / Reconstruction of the brewery structure using post-tensioned ceiling

Zavadil, Bronislav January 2013 (has links)
Aim of this master's thesis is an optimized design of locally supported ceiling slab of building of social center with account of span of columns and height of slab. Structure must be assessed in terms of limit state and service limit state by ČSN EN 1992-1-1 General rules and rules for buildings after design.
309

Žáruvzdorné výrobky určené pro metalurgii hliníku / Refractory Products for Aluminum Metallurgy Industry

Kupcová, Zuzana January 2014 (has links)
The master´s thesis focuses on high-alumina refractory materials used mainly in aluminia metallurgy. Teoretical part of this thesis is aimed at distribution of refractory materials, possibilities of its production and raw material basis. Characteristic properties are described as well as application possibilities in aluminium technology. In final part of this thesis experimental data are evaluated to obtain physical, mechanical, chemical properties of high-alumina refractory materials. Those are used for economical optimalization of raw materials.
310

Modelování a statická analýza stropní konstrukce v programu ANSYS. / Simulation and statically analysis of cieling structure by Ansys FEM program.

Obršlík, Petr January 2014 (has links)
This thesis mainly deals with modeling and static analysis of the ceiling structure in the basic environment of ANSYS. The first part is focused on verifying correctness of the model most stressed parts of the structure with a simple hand-static calculation by the process of stress on a continuous beam. The main part is devoted to modeling composite structure, element types, specifying loads and boundary conditions by ANSYS FEM program. In the end, there are the results of stress and deflection presented, and the structure is evaluated at the ultimate limit state and serviceability limit state.

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