• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 9
  • 6
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 23
  • 23
  • 9
  • 9
  • 8
  • 8
  • 8
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • 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.
11

Modelagem numérica de ligações viga-coluna em aço sob momento fletor e força normal. / Numerical modeling of steel beam-to-column joints subjected to bending and normal force.

Monique Cordeiro Rodrigues 14 August 2009 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As ligações desempenham um papel fundamental no comportamento global das estruturas de aço. Inúmeros trabalhos de pesquisa têm sido desenvolvidos para entender o comportamento real de uma ligação e sua influência na resistência global dos pórticos. Atualmente, a Norma Brasileira de estruturas de aço de edificações, NBR 8800, considera o comportamento das ligações entre duas situações extremas: rígidas, onde não ocorre nenhuma rotação entre os membros conectados, transferindo momento fletor, força cortante e força normal; ou flexíveis, caracterizadas pela liberdade de rotação entre os membros conectados, impedindo a transmissão de momento fletor. Outras normas de projeto de estruturas de aço, consideram que as ligações apresentam um comportamento intermediário, ou seja, semi-rigídas, que podem estar submetidas a uma combinação de momento fletor e esforço normal. Porém, mesmo com a combinação, estas normas não consideram a presença de esforço normal (tração e/ou compressão). Uma limitação empírica de 5% da resistência plástica da viga é a única condição imposta no Eurocode 3. Para o estudo da ligação semi-rigída será utilizada a filosofia do Método das Componentes, que verifica a resistência da ligação e sua classificação quanto à rigidez rotacional, desenvolvida através de modelos mecânicos (modelos de molas). O objetivo deste trabalho é descrever alguns resultados de caracterização de ligações viga-coluna com placa de extremidade ajustada à altura da viga obtidos através de um modelo de elementos finitos. Para tal, será realizada uma análise não-linear geométrica e de material. Esta análise possibilitará avaliar os principais parâmetros que influenciam no comportamento deste componente no que diz respeito a sua avaliação em termos de distribuição de tensões e deformações no modelo de forma global. / The joints develop a fundamental role in the global behaviour of steel structures. Several researches are being developed to understand the real behaviour of a joint and its influence in the global frame capacity and beam-to-column joints of the steels buildings. Nowadays, the Brazilian Code of the Steel Portal Frame Design, NBR 8800, considers the joint behaviour between two extreme situations: rigid, where any rotations dont occur between the connected members, transfering substantial bending moments, and also shear and axial forces; or pinned, its characterised by almost free rotation movement between the connected elements that prevents the transmission of bending moments. However, some actual codes of the steel structures project, consider that the joints present an intermediate behaviour, in other words, semi-rigid, that may be subjected to a combination of bending moment and axial force. But, these codes dont consider the presence of axial force (tension and/ or compression). A single empirical limitation of 5% of the beams plastic axial capacity is the only enforced provision in Eurocode 3. This filosofy design is based on components method, for joint capacity evaluation and its classification concerning the joint rotation stiffness. This component method is based on mechanical models (spring model) created by an association of rigids and flexible joints components represented by a translacional spring. The objective of this present work is describing some results of flush endplate semi-rigids beam-to-column joints obtained across finite elements method and geometric and material non-linear analises. These consider the main parameters that influence the components behaviour about the stress and deformation distribution.
12

[en] STRUCTURAL EVALUATION OF END PLATE STEEL SEMI-RIGID CONNECTIONS / [pt] AVALIAÇÃO ESTRUTURAL DE LIGAÇÕES SEMI-RÍGIDAS EM AÇO COM PLACA DE EXTREMIDADE

FERNANDO BUSATO RAMIRES 30 April 2004 (has links)
[pt] As ligações viga-pilar desempenham uma função fundamental para a determinação do comportamento real de estruturas de aço. Portanto torna-se necessária uma avaliação muito criteriosa das reais características geométricas e mecânicas destas ligações, substituindo as tradicionais considerações idealizadas, rígida e flexível, pela modelagem semi-rígida.Atualmente um dos métodos mais utilizados para caracterização de ligações semi-rígidas se fundamenta no método das componentes, descrito pelo Eurocode 3, que consiste na determinação da resistência e rigidez dos elementos de maior influência no comportamento de uma ligação. Com a intenção de se desenvolver um estudo sobre as ligações semi-rígidas, inicialmente foi implementado computacionalmente um sistema de análise e dimensionamento capaz de avaliar o comportamento estrutural destas ligações a partir da informação das propriedades geométricas de ligações viga- pilar executadas com placa de extremidade, produzindo uma base de dados para um projeto estrutural mais seguro. Adicionalmente também foi executado um estudo sobre a otimização do dimensionamento de ligações semi-rígidas, através da criação de um sistema para determinação do modelo ótimo, utilizando-se algoritmos genéticos. Neste sistema, através da variação de parâmetros geométricos, determinados de acordo com a necessidade do usuário, obtém- se o modelo ideal de comportamento dentro de uma gama de soluções possíveis. Finalizando o presente estudo sobre ligações semi-rígidas, apresenta-se uma nova metodologia para consideração de ligações aparafusadas com placa de extremidade de altura variável, (header plate), que tradicionalmente são consideradas como flexíveis. Estas ligações foram analisadas através do método das componentes, determinando suas limitações de resistência à flexão e ao corte, juntamente com sua rigidez rotacional, efetuando-se modificações nas componentes apresentadas no Eurocode 3. / [en] The beam-to-column connections play fundamental role in the determination of the real behavior of steel structures. Therefore it is imperative to proper evaluate and consider the real geometric and mechanical properties of these connections, substituting the traditional idealized considerations, rigid and flexible, for the semi-rigid modelling approach. Nowadays one of the most used methods in the semi-rigid connection design is named the components method, described in the Eurocode 3. This method is based on the determination of the connection bending capacity and initial stiffness from the most relevant structural element parts. The main objective of this investigation was to evaluate the semi-rigid connection structural response. This was made by the development of a computer system capable to properly evaluate the behaviour of these connections. This program used the end plate beam-to-column connection material and geometric properties to fulfil this objective, producing a comprehensive database later to be used for more reliable structural project. Additionally an optimisation module was also implemented on the semi-rigid connection program, using genetic algorithms, where through the variation of certain geometric parameters, chosen in accordance to the user's requirements, the ideal connection structural behaviour could be determined from a range of pertinent solutions. Concluding the present study an alternative procedure is proposed for header plate connections where traditionally only shear was assumed to be transmitted. These connections were analysed according to the component method, to determine their bending and shear resistance, initial stiffness and rotation capacity, through modifications made on the relevant structural components presented in Eurocode 3 standard.
13

Modelagem numérica de ligações viga-coluna em aço sob momento fletor e força normal. / Numerical modeling of steel beam-to-column joints subjected to bending and normal force.

Monique Cordeiro Rodrigues 14 August 2009 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / As ligações desempenham um papel fundamental no comportamento global das estruturas de aço. Inúmeros trabalhos de pesquisa têm sido desenvolvidos para entender o comportamento real de uma ligação e sua influência na resistência global dos pórticos. Atualmente, a Norma Brasileira de estruturas de aço de edificações, NBR 8800, considera o comportamento das ligações entre duas situações extremas: rígidas, onde não ocorre nenhuma rotação entre os membros conectados, transferindo momento fletor, força cortante e força normal; ou flexíveis, caracterizadas pela liberdade de rotação entre os membros conectados, impedindo a transmissão de momento fletor. Outras normas de projeto de estruturas de aço, consideram que as ligações apresentam um comportamento intermediário, ou seja, semi-rigídas, que podem estar submetidas a uma combinação de momento fletor e esforço normal. Porém, mesmo com a combinação, estas normas não consideram a presença de esforço normal (tração e/ou compressão). Uma limitação empírica de 5% da resistência plástica da viga é a única condição imposta no Eurocode 3. Para o estudo da ligação semi-rigída será utilizada a filosofia do Método das Componentes, que verifica a resistência da ligação e sua classificação quanto à rigidez rotacional, desenvolvida através de modelos mecânicos (modelos de molas). O objetivo deste trabalho é descrever alguns resultados de caracterização de ligações viga-coluna com placa de extremidade ajustada à altura da viga obtidos através de um modelo de elementos finitos. Para tal, será realizada uma análise não-linear geométrica e de material. Esta análise possibilitará avaliar os principais parâmetros que influenciam no comportamento deste componente no que diz respeito a sua avaliação em termos de distribuição de tensões e deformações no modelo de forma global. / The joints develop a fundamental role in the global behaviour of steel structures. Several researches are being developed to understand the real behaviour of a joint and its influence in the global frame capacity and beam-to-column joints of the steels buildings. Nowadays, the Brazilian Code of the Steel Portal Frame Design, NBR 8800, considers the joint behaviour between two extreme situations: rigid, where any rotations dont occur between the connected members, transfering substantial bending moments, and also shear and axial forces; or pinned, its characterised by almost free rotation movement between the connected elements that prevents the transmission of bending moments. However, some actual codes of the steel structures project, consider that the joints present an intermediate behaviour, in other words, semi-rigid, that may be subjected to a combination of bending moment and axial force. But, these codes dont consider the presence of axial force (tension and/ or compression). A single empirical limitation of 5% of the beams plastic axial capacity is the only enforced provision in Eurocode 3. This filosofy design is based on components method, for joint capacity evaluation and its classification concerning the joint rotation stiffness. This component method is based on mechanical models (spring model) created by an association of rigids and flexible joints components represented by a translacional spring. The objective of this present work is describing some results of flush endplate semi-rigids beam-to-column joints obtained across finite elements method and geometric and material non-linear analises. These consider the main parameters that influence the components behaviour about the stress and deformation distribution.
14

Vybrané metodické přístupy k tvorbě regionální populační prognózy: případová studie na úrovni Jihočeského kraje / Selected Methodical Approaches to Regional Population Forecast: A case study in the South Bohemian Region

Říha, Vojtěch January 2017 (has links)
Selected Methodical Approaches to Regional Population Forecast: A case study in the South Bohemian Region Abstract The aim of this thesis is to introduce selected methodological approaches to population forecasts, focusing on the regional level and considering different lengths of time series. Specific procedures are applied to create a population forecast for the South Bohemian Region. In the theoretical part of this thesis, the stages of population forecasts processing are determined. The Cohort Component method with migration, which can be used to create population forecast, is characterized. Another part describes selected analytical models and functions for partial mortality, fertility and migration forecasts, including Indirect estimation of net migration. To extrapolate parameters, selected trending functions and the Box-Jenkins methodology are characterized in the part of the time series analysis. The analytical part of this thesis focuses on the creation of the South Bohemian Region forecast from short initial time series and long initial time series. From short initial time series, the partial forecast of mortality is analyzed by the Heligman-Pollard model, the partial forecast of fertility is analyzed by the Beta function and the partial forecast of migration is analyzed by 25%, 50% and 75%...
15

Prognóza vývoje obyvatelstva Moravskoslezského kraje do roku 2050 / Moravskoslezský region population forecast to 2050

Papřoková, Petra January 2017 (has links)
Moravskoslezský region population forecast to 2050 Abstract The main goal of this thesis is to calculate Moravskoslezský region population forecast to 2050 and show how future population growth will likely be in the next decades. It includes a detailed population development analysis which is an important part of this thesis. Moravskoslezský region is still one of the most populous regions of Czechia, despite of natural decrease and negative net migration in past 21 years (except 2007 and 2008). Based on the analysis, we can assume that population decline will continue in the future and population forecast results confirm this hypothesis. Declining population size will be followed by significant age-structure changes in population and progressive demographic ageing. From the perspective of future population development Moravskoslezský region will face brand new situations and related problems. Keywords: population forecast, Moravskoslezský region, analysis of population development, age structure, fertility, mortality, migration, regional development, cohort-component method
16

Dostupnost sociálních služeb pro seniory v Karlovarském kraji v současnosti a za 50 let / Availability of social services for seniors in the Karlovarsky region now and in 50 years

Zelinka, Jan January 2015 (has links)
Master thesis aims to evaluate the accessibility of social services in Karlovarsky region. The thesis is focused on the demographics of seniors and social services intended for them, specifically retirement homes. In addition to analyzing the accessibility of social services is elaborated demographic projection of region's population over the next 50 years. In the theoretical part is described the definition of social policy and the fundamental theoretical principles, types and functions. This part also describes the legislative framework of social policy in the Czech Republic. In relation to social policy are presented issues of community planning as a tool for the implementation of social policy in the Karlovarsky region. The conclusion of theoretical part is devoted to the theory of demographic projections and describes the basic projection methods. The practical part in the introduction focuses on general and demographic characteristics of the Karlovarsky region and the current state of social services for the elderly, specifically homes for the elderly. The second half of the practical part presents a demographic projection of region's population over the next 50 years and is focusing on senior component whose proportion in the population will increase. This projection is calculated by the component method without migration. The conclusion of the practical part is comparing the initial state of social services and the anticipated development of seniors. It also describes community plan in the Karlovarsky region with emphasis on the development of social services for seniors. Documents drawn up by the Karlovarsky region on issues of social services and conclusions of this thesis suggest that there is no need to increase capacity, but rather to focus on the change in the structure of users and ensure that these services are provided to people whose health condition really requires this kind of complex social care.
17

Studie styčníků rámových ocelových konstrukcí / Study of joints of frame steel structures

Cikánek, Ondřej January 2017 (has links)
Master's thesis „Study of joints of frame steel structures“ examine certain analysis types of frame steal joints, which are analysed both by component method and by specialized software IDEA RS. Obtained results are compared by both methods, in terms of load-bearing capacity and in terms of stiffness. Theoretical joints stiffness calculation according to standard ČSN EN 1993-1-8 is included in the introductory part of the thesis. In the second part, joints are designed to bear inner forces and moments, which were created by load combination effects and then analysed.
18

Komponentmetoden : En studie som berör tillämpningen av redovisning i komponenter utifrån fastighetsförvaltande bolag / Component accounting : A study concerning the application of componentization in accounting based on real estate companies

Almén, Isac, Olausson, Frida, Sonesson, Martin January 2023 (has links)
Komponentmetoden berör den bokföringsmässiga hanteringen av materiella anläggningstillgångar. I många avseenden kan dessa bestå av olika delar förknippade med olika förbrukningstakt och nyttjandeperioder. Fastigheter är en typisk sådan anläggningstillgång där exempelvis stomme, tak och fasad då utgör sådana komponenter vilka enligt komponentmetoden ska redovisas separat. Företag som tillämpar K3-regelverket behöver förhålla sig till detta. Följande studie fokuserar på redovisning av komponenter utifrån fastighetsförvaltande företag. Studien ämnar undersöka skillnader samt likheter i företagens tillämpning såväl som hur detta förhåller sig mot publicerade vägledningar kring hur metoden kan tillämpas. Likaså söker studien förståelse för vilka implikationer komponentmetoden medför för företagen. Studien utgår från en kvalitativ metod där intervjuer av fyra företag utgör grunden för det empiriska materialet. Vidare har en komparativ multipel fallstudiedesign använts för att uppnå studiens syfte. Resultatet påvisar att komponentmetodens tillämpning är företagsunik och består i många fall av uppskattningar hos respektive företag. Även likheter mellan företag och vägledningar har såväl identifierats. De implikationer som följer beror delvis på hur metoden tillämpas. Ökade avskrivningskostnader, jämnare resultat, en ökning av fastigheternas bokförda värden samt dess påverkan på redovisningens jämförbarhet är dock att betrakta som några av de huvudsakliga konsekvenserna. / Component accounting concerns the accounting management of tangible fixed assets. In many cases, these assets consist of different parts with varying economical and technical lifespans. Real estates are regarded as such assets whereby the building frame, roof and facade could be examples of distinguished components that should be accounted for separately. Swedish companies applying the K3-framework need to manage their accounting accordingly. This study´s focus relates to real estate companies’ application of component accounting. The aim of the study is to investigate differences and similarities between different companies, also in comparison to published guidelines on this topic. Furthermore, the study seeks to understand the implications of component accounting. A qualitative method has been applied where interviews have been conducted with four companies that form the basis of the empirical data. To achieve the purpose of the study a comparative multiple case design has been used.  The results show that component accounting is uniquely applied between companies and is often characterized by estimations. However, similarities between the companies as well as the guidelines do also exist. The implications that follow depend in part on how it´s applied, although increased depreciations, profit smoothing, increased book values and the componentization´s impact on comparability have been found to be some of the main consequences.
19

Revisorernas inflytande : Komponentmetoden, en rättvisande bild och den institutionella teorins förklaring av mindre fastighetsföretags val av principbaserad redovisning

Backman, Mikaela January 2016 (has links)
No description available.
20

Analysis of Tension-Zone Resistance in Bolted Steel Connections : Component Method according to Eurocode3

Hamodi, Sara, Fahandezh Sadi, Taha January 2017 (has links)
In order to predict the behaviour of bolted steel connections, different methods can be applied to calculate the design tension resistance. In this thesis, the tension resistance is evaluated in the context of the so called Component Method according to Eurocode 3 part 1-8. The design approach establishes a unified procedure of modelling steel joints. Each joint configuration is decomposed into its basic components depending on loading type. In order to design the resistance of components subjected to tensile forces, a simple substitute model, the so-called Tstub flange is adopted. The Component Method is rather complicated to apply for all joint configurations. Therefore, the aim of this thesis is to create a brief and facilitated handbook covering the most common types of connections Kadesjös’ engineers deal with. The topic to be studied is rather comprehensive. Thus, this work is only focusing on the resistance calculation of components located in tension zone of HEA-sections in order to go deeper into the equivalent T-stub approach. To get a complete view about the designing procedure, general information about the Component Method are gathered by a literature study. Thereafter, the technical rules for calculation introduced in codes and standards were used to generate a general solution algorithm for two different connection configurations. The calculations have been performed using Mathcad, and the obtained results from a parametric analysis for particular profiles in each example are then summarised in tables and diagrams using Microsoft Excel. / Att förutse skruvförbands beteende kan kräva tillämpning av diverse metoder. Metoderna används för att kalkylera den dimensionerande lastkapaciteten. I denna avhandling värderas lastkapaciteten i enlighet med den så kallade Komponentmetoden från del 1-8 i Eurokod 3. Denna dimensioneringsmetod fastslår en enhetlig procedur när det gäller modelleringen av stålförband. Varje förbandstyp bryts ner till sina baskomponenter med avseende på belastningstypen. För att beräkna den dimensionerande lastkapaciteten för dragbelastade komponenter används en förenklad substitutionsmodell en så kallad T-knut. Komponentmetoden är något komplicerad att tillämpa för alla former av skruvförband. Därmed är den huvudsakliga ambitionen med arbetet att skapa en kortfattad handbok vars syfte är att täcka de vanligaste typerna av skruvförband som Kadesjös konstruktörer använder sig av. Ämnet som kommer att studeras är relativt omfattande, således bestämdes det att i huvudsak sätta fokus på bärförmågan hos komponenter i dragzonen för HEA-profiler och därav dyka djupare i den ekvivalenta T-knutmetodiken. För att få en helhetsbild av dimensioneringsprocessen samlades allmän information om komponentmetoden genom litteraturstudier. Därefter användes dimensioneringsreglerna, presenterade i koder och standarder, för beräkning av lastkapacitet. Dessa utnyttjades för att generera en lösningsalgoritm för två skilda förband. Beräkningen genomfördes med hjälp av beräkningsprogrammet Mathcad. De erhållna resultaten, från en parametrisk analys för särskilda profiler i varje exempel, sammanfattades i form av tabeller och diagram med hjälp av Microsoft Excel.

Page generated in 0.0625 seconds