Dissertations / Theses on the topic 'The screw connection'

This research introduces a proposed model for predicting tilting angle and limit states of single-fastened cold-formed steel-to-steel shear connections. Predictions are validated through an experimental study considering ply configuration and a single Hex #10 -washer head fastener, centered in a 102 mm by 102 mm three boundary window. The fastener tilting angle is captured using an automated, optical non-contact measurement procedure. The results are used to identify cold-formed steel shear connection deformation as load progresses, including tilting, bearing, and combined tilting bearing at the plies and thread tension, shear and bearing fastener failure. Results shows that fastener tilting plays a kinematic affect for the connection. Fastener tilting is predicted in function of ply thickness and fastener pitch. Local ply bending deformation is reported to be the main deformation of the connection during fastener tilting. While fastener bending and shear failure occurred if the fastener does not tilt.
Master of Science

Thesis (M.S.)--Missouri University of Science and Technology, 2009.
Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 23, 2009) Includes bibliographical references (p. 52).

This study aims to validate a screw joint simulation model used by BAE Systems in LS-DYNA during blast simulations. It is important that the screw joint simulation model is physically correct, since the simulation results can influence major design decisions. The study provides a short overview on the subject of bolts and screws, material deformation and stress and strain in materials, of the finite element method (FEM) and on some specific numerical methods used in this study. BAE Systems started a validation project of the screw joint simulation model in 2015, but it was not finished due to other priorities. In this older project some drop-tower tests measuring the axial force in a screw joint were conducted. These old tests can now serve as validation data for the screw joint simulation model. The screw joint simulation model used by BAE Systems is dependent on a special kind of finite element formulation; a so called beam element. This study provides a finite element analysis on this simulation model, which is implemented through an established industry FEM solver called LS-DYNA. The validation of the screw joint simulation model is done against three drop-tower experiments performed at 900, 1000 and 1100mm drop height respectively. The drop-tower experiments were replicated in LS-DYNA, with a prescribed velocity on the falling parts rather than simulating a free fall and non-elastic impact. A comparison between the simulation model using beam elements, that is used by BAE Systems, and a similar simulation model using solid elements is presented as part of the validation. To make sure that the result of the study is confident, a local mesh convergence study and a study of the mass scaling numerical method in LS-DYNA is also presented. The results show that the screw joint simulation model using beam elements is valid according to the available experimental data. In one of the experiments, where the drop-test was performed twice, an average maximum force on the screw was measured to be 33.5+-4.8 kN. Simulations of the same case, under the same conditions, using beam elements resulted in a maximum force on the screw of 35.4 kN, well within the experimental result range. In the other two drop-tower experiments, the simulated results showed correlation considering the error sources in the simulation model and the statistical spread that is present in the experimental results. The simulation model using beam elements is also similar to the results using solid elements, which also indicates that the beam model is valid. All in all, it is shown that the beam model can be used to produce safe results that either overestimate or place the simulations of the axial force in the screw in the upper spread of the measurements.

This study investigated the vibration serviceability of timber structures with dowel-type connections. It addressed the use of such connections in cutting-edge timber structures such as multi-storey buildings and long-span bridges, in which the light weight and flexibility of the structure make it possible that vibration induced by dynamic forces such as wind or footfall may cause discomfort to occupants or users of the structure, or otherwise impair its intended use. The nature of the oscillating force imposed on connections by this form of vibration was defined based on literature review and the use of established mathematical models. This allowed the appropriate cyclic load to be applied in experimental work on the most basic component of a dowel-type connection: a steel dowel embedding into a block of timber. A model for the stiffness of the timber in embedment under this cyclic load was developed based on an elastic stress function, which could then be used as the basis of a model for a complete connector. Nonlinear and time-dependent behaviour was also observed in embedment, and a simple rheological model incorporating elastic, viscoelastic and plastic elements was fitted to the measured response to cyclic load. Observations of the embedment response of the timber were then used to explain features of the behaviour of complete single- and multiple-dowel connections under cyclic load representative of in-service vibration. Complete portal frames and cantilever beams were tested under cyclic load, and a design method was derived for predicting the stiffness of such structures, using analytical equations based on the model for embedment behaviour. In each cyclic load test the energy dissipation in the specimen, which contributes to the damping in a complete structure, was measured. The analytical model was used to predict frictional energy dissipation in embedment, which was shown to make a significant contribution to damping in single-dowel connections. Based on the experimental results and analysis, several defining aspects of the dynamic response of the complete structures, such as a reduction of natural frequency with increased amplitude of applied load, were related to the observed and modelled embedment behaviour of the connections.

The main focus of the dissertation thesis is determine the size of the fastening screw connection and fastening torque of the connection, which will be applied during assembly of the instrument current transformers and sensors. The large part of thesis is an experimental measurement of the proposed configurations of connections and modelling (simulating) certain model of connections in Ansys and SolidWorks analysis programs. The result of the dissertation will be design of tightening of the connection according to transient resistance and thermal losses.

I denna studie analyseras en byggnad producerad med volymmoduler med lastbärande stomme av KL-trä. Resultat från analysen av hur laster påverkar byggnaden jämförs med resultat från motsvarande analys av en stomme producerad med reglar och balkar. I studien redovisas de krafter byggnaden utsätts för och förband mellan vägg och bjälklag. Ett förslag på förband mellan vägg och bjälklag presenteras och en jämförelse av bärförmågan i en volymmodul med KL-trästomme kontra träregelstomme genomförs.
In this study, a building produced with volume modules with a load bearing CLT-system is analyzed. Results from the analysis of how loads affect the building are compared with results from the corresponding analysis of a conventionally produced volumetric element and how vertical loads as well as wind loads affect its design. In the study, the forces that the building is exposed to are examined and the connection between wall and floor joints is designed. The forces and torque a construction built up of volume modules is exposed to are also presented. In the study the connection between the floor joints and the supporting wall is designed according to Eurocode. A comparison is presented with respect to the load carrying capacity of a volume module with CLT and a conventional load bearing frame.

The subject of this master’s thesis was desingn and assessments the connection of two buildings by footbridge corridor. The structure was designed as a lattice structure without verticals. Construction is stored on two pillars lattice design. Cladding footbridge was cosidered by glazing. Construction is freestanding and doesn’t load bordering adjacent buildings.

In this project, the main research objective is intend to seek criteria for evaluating the capacity of BAC screw fasteners with mixed configuration of waterproof seal washer, sealer tape and different pre-drill holes to determine shear and tension strength values for the screws used in cold-formed steel connections. The thesis presents the design methods and test program conducted to investigate the behavior and strength of the screw connections in shear and tension test. Test results were compared with AISI design provisions to determine if new design equations will be developed for those screws used in BAC cooling tower applications. LRFD resistance factors and ASD safety factors were investigated to the proposed design equations.

This study focused on the non-linear finite element modelling procedure, utilising the explicit dynamic analysis technique, and how the various modelling parameters affect the accuracy. The computer modelling of screwed connections is a complex task, and the objective was to investigate the different modalities of finite element modelling to effectively analyse thin sheet steel screwed connections, through calibration against test data found within existing literature. Several aspects of the modelling procedure were examined, including contact definitions, the effective control of the applied load and how it affects the energy output of the finite element model. The final calibrated model was utilised in subsequent parametric studies, which investigated the effect of the steel sheet thickness, as well as the number of the screws used. Results concluded that the finite element model could effectively simulate the expected experimental behaviour of these connections.
Disseration (MEng)--University of Pretoria, 2016.
Civil Engineering
MEng
Unrestricted

This thesis aims to develop a comprehensive usable engineering design approach to the fatigue analysis of threaded connections. Although primarily concerned with the fatigue-fracture mechanics behaviour of screw threads, a broad review of stress analysis investigations in such connections is reported. Connection types, their functions and standardisation authorities are presented with the purpose of familiarising the reader with the subject and the options available to the design of threaded fasteners. Fatigue crack initiation is discussed with reference to the specific setting of a critical thread root. A crack initiation model is adapted for employment in thread root design. A novel weight function approach is developed for use in the determination of stress intensity factors for threaded connections. A generic solution is proposed valid for the fatigue crack growth from any thread root under any symmetrical stress system. Its development and discussion is examined in detail, remaining close to its proposed application. Two engineering situations where the chief structural components are comprised of threaded members are taken as case studies. The background to each situation is elaborated in detail and full-scale fatigue tests were conducted on the critical components. In all, fourteen full-scale tests under constant and variable amplitude loading are reported. The results of these are analysed and used to validate the fatigue crack initiation and propagation models. Useful observations which are helpful to understanding the fracture mechanisms operating during the fatigue of threaded connections are reported. Material and environmental considerations are examined and a survey of relevant materials and their behaviour in environments associated with threaded fasteners is presented. The merits or otherwise of some common engineering practices are discussed with regard to fatigue. A method has been developed for predicting fatigue life in large threaded connections under random loading. Experimental results have been gathered on two types of components used on certain oil rigs, tether joints and drill strings. The agreement found between prediction and experiment is appreciably better than by previous methods of analysis and also points to aspects open to further improvement.

Several thousand tests throughout the world have been conducted on the shear strength of screw connections in cold-formed steel, however, little to no research has been conducted on how various thicknesses of insulation placed between two sheets of steel, such as a steel panel and structural supporting member, affects a screw's shear strength. Elemental tests were conducted as part of this study at Virginia Tech where rolled fiberglass insulation was placed between two pieces of steel connected by self-drilling screws and tested to failure. The results were compared to the North American Specification for the Design of Cold-Formed Steel Structural Members to determine if the presence of insulation affected the shear and tensile strengths of screw connections involving insulation. A series of diaphragm tests were also preformed to confirm the elemental tests. While the presence of insulation between two steel sheets connected by screws reduces the shear strength of the connection, the current equations for predicting this strength in the North American Specification are adequate. When the data acquired from this study and the screw shear data obtained in past research were combined, it was clear that the data collected during this study fell within the scatter of the data used to develop Section E4.3 of the North American Specification neglecting the need for modification.
Master of Science

The main objective of the master’s thesis is to study the influence of phosphate coating structure on the mechanical properties of screw connection. The theoretical part describes the conventional phosphating process and it is followed by an analysis of current knowledge of phosphating technology. Experiments are carried out on screw valves mounted to a high pressure diesel pump by Bosch Diesel s.r.o., made of unalloyed carbon steel. To investigate the effect of the structure on the connection sealing, twelve kinds of phosphate coatings varying in one process parameter were prepared. The monitored parameters determining the phosphate structure are – type of phosphate and activation bath, its temperature and concentration and time of immersion. The sealing connection is examined during simulated assembly process by angle controlled tightening while measuring torque and permanent material deformation. Prepared layers are characterized by determination of weight per unit area and their structure observed by electron microscope.

The main aim of this master´s thesis is designing parking garage including access ramps situated in Ústí nad Labem. Dimensions of parking garage is 58,6x31,1 m. As a support system of construction are used steel-concrete composite elements. The calcuation was done by manual calcuation.

The aim of my thesis is the design of centrifugal brakes to prevent twisting of the combustion engine with pneumatic compactor. In the first part of my thesis I deal with existing and similar systems that prevent over speeding. In the second part I deal with the design of its own centrifugal brake. This includes basic functional, strength, thermal calculation, design of components and fabrication drawings according to the assignment.

This thesis introduces an approach for modeling the monotonic and cyclic response of cold-formed steel framing screw-fastened connections in commercial finite element programs. The model proposed and verified herein lays the groundwork for seismic modeling of cold-formed steel (CFS) framing including shear walls, gravity walls, floor and roof diaphragms, and eventually whole building seismic analysis considering individual fastener behavior and CFS structural components modeled with thin-shell elements. An ABAQUS user element (UEL) is written and verified for a nonlinear hysteretic model that can simulate pinching and strength and stiffness degradation consistent with CFS screw-fastened connections. The user element is verified at the connection level, including complex cyclic deformation paths, by comparing to OpenSees connection simulation results. The connection model is employed in ABAQUS shear wall simulations of recent monotonic and cyclic experiments where each screw-fastened connection is represented as a UEL. The experimental and simulation results are consistent for shear wall load-deformation response and cyclic strength and stiffness degradation, confirming the validity of the UEL element and demonstrating that light steel framing performance can be directly studied with simulations as an alternative to experiments.
Master of Science

A aplicação da madeira como material estrutural na construção civil é amplamente difundida em coberturas residenciais e comerciais, construção de residências ou em obras de grande porte como pontes. Freqüentemente ocorre a necessidade de ligações entre peças estruturais. Uma das possibilidades de ligação é a utilização de parafusos auto-atarraxantes solicitados por esforços de tração, diferente da maioria dos casos de ligações, nas quais pinos estão solicitados por forças laterais. Um tipo particular de parafuso auto-atarraxante é o torx, que possui rosca em toda a sua extensão, possibilitando uma outra forma de arranjo de ligação que facilita a execução das ligações entre as peças estruturais. Este parafuso possui uma grande resistência que traz à industrialização das estruturas de madeiras. O objetivo desta pesquisa é determinar, de maneira experimental, a resistência de ligações utilizando parafusos torx auto-atarraxantes submetidos a esforços axiais de tração, em peças de madeira, avaliando a influência de diversos fatores, tais como: direção de fixação dos parafusos em relação às fibras, efeito de grupo teor de umidade, massa específica da madeira e espaçamentos entre parafusos. Foram utilizadas as espécies: Pinus Taeda (Pinus taeda L.), Eucalipto Grandis (Eucalyptus grandis) e Cupiúba (Goupia glabra).
Timber as a structural material civil in construction is widely used in framework, construction of houses or larger construction as bridges. The use of connections among structural members is frequently required. One of the connection possibilities is the use of lag screws in axial withdrawal load, differently from most cases of connections in which they are laterally loaded. A peculiar type of lag screw is the torx, which possesses thread along its extension, making possible another form of connection arrangement that facilitates the execution of the connections among the structural pieces. This lag screw has a high strength and facilitates the industrialization of timber structures. The aim of this research is to determine, in an experimental way, the strength of connections using torx lag screws in withdrawal loads, evaluating the influence of several factors, such as direction of the lag screws in relation to grain, group effect, moisture content, density of wood and spacings among screws. The species used were: Pinus Taeda (Pinus taeda L.), Eucalipto Grandis (Eucalyptus grandis) and Cupiúba (Goupia glabra).

The topic of the thesis is a project of roof of a multifunctional sport object with a ground-plan covering area 35x48m, and maximum height of 16m. This construction is projected for Brno and its surroundings. The project of roofing is evolved in two different variants. First one is formed by double-jointed arched latticed truss. Supporting components such as purlins, lateral and longitudal bracings, frontal column and anchorage are designed and assessed in static calculation. At the end of the thesis, comparison of both variants is elaborated. Design documentation, which consists of dispositional drawing, drawing of truss for manufacturing, drawing of indicative details and plan of anchorage, is a part of the thesis.

Thesis (MEng)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: The South African National Standard for the structural use of cold-formed steel (SANS 10162-2) provides capacity prediction models for screwed connections. Screwed connections are designed against shear failure of the screw(s), section tear-out, net section failure and tilt-andbearing failure. Previous studies (Rogers & Hancock, 1997) showed that the capacity is typically determined by the tilt-and-bearing type failure mode. The aim of this document is to report on the reliability of single screwed connections in cold-formed steel against this critical failure mode. Predicted nominal capacities depend on the ultimate tensile strength of the steel, the thickness of the connected plates and the diameter of the screw. Design capacities are obtained by multiplying the nominal capacities by a capacity reduction factor of 0.5, according to SANS 10162-2. Reliability is assessed by means of FORM analyses, taking uncertainty in the prediction model and variability of input parameters into account. Laboratory testing of 222 single screwed connections allowed to statistically describe the model factor, i.e. the ratio of actual tested- over unbiased predicted capacity. For each connection, the steel strength, plate thickness and screw diameter were measured, with the measured values used to predict capacity. This implies that the model factor accounts for uncertainty in the prediction model and experimental setup, while the variability of input parameters is separately accounted for through appropriate statistical modelling. Variability in the input parameters was described using appropriate statistical distributions from expert literature (Holicky, 2009:199; JCSS, 2000). For steel strength, the mean value and standard deviation were obtained from tensile tests, while mean values and standard deviations of the plate thickness and screw diameter were obtained from the above mentioned measurements. The experimental work and numerical analysis resulted in a model factor with a mean just exceeding unity and a small standard deviation. This suggests that the design code under consideration is able to accurately predict the nominal capacity of screwed connections. The FORM analysis resulted in computed reliability indexes significantly higher than the corresponding target values which suggest conservative and reliable design formulations. Die eksperimentele werk en numeriese analise het gelei tot 'n model faktor met 'n gemiddeld hoër as een en 'n klein standaardafwyking. Dit dui daarop aan dat die ontwerp-kode onder oorweging in staat is om die nominale kapasitiet van skroef verbindings akkuraat te voorspel. Die betroubaarheid analise het gelei tot betroubaarheidsindekse aansienlik hoër as die ooreenstemmende teiken waardes wat daarop dui dat die ontwerp formulerings betroubaar en hoogs konserwatief is.
AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse Nasionale Standaard vir die strukturele gebruik van koud gevormde staal (SANS 10162-2) bied voorspellingsmodelle vir die kapasitiet van skroef verbindings. Skroef verbindings word ontwerp teen skroef faling, staal profiel faling, die uitskeer van skroewe en ook faling weens skroef kanteling. Vorige studies (Rogers & Hancock, 1997) het getoon dat die kapasiteit gewoonlik bepaal word deur die skroef-kantel falingsmodus. Die doel van hierdie navorsing is om verslag te doen oor die betroubaarheid van tipiese enkel skroef verbindings in koud gevormde staal strukture teen hierdie kritiese falingsmodus. Voorspelde nominale kapasiteite hang af van die treksterkte van die staal, die dikte van die verbonde profiele en die diameter van die skroef. Volgens die SANS 10162-2 word die ontwerp kapasiteit verkry deur die nominale kapasiteit met 'n kapasiteitsverminderingsfaktor van 0.5 te vermenigvuldig. Betroubaarheid word ontleed deur middel van ʼn eerste orde betroubaarheidsmetode analise, met die in ag neming van onsekerheid in die voorspellingsmodel en wisselvalligheid van die parameters. Laboratoriumtoetse van 222 enkel skroef verbindings het ʼn statistiese beskrywing van die model faktor toegelaat. Die model faktor is bereken as die verhouding tussen die getoetste kapasitiet en die voorspelde kapasitiet. Die staal sterkte, profiel dikte en skroef diameter is gemeet vir elke verbinding met die gemete waardes wat gebruik is om die kapasiteit te voorspel. Dit beteken dat die model faktor slegs onsekerhede in die voorspellingsmodel en van die eksperimentele opstelling in ag neem, terwyl die wisselvalligheid van die parameters afsonderlik in ag geneem word deur toepaslike statistiese modellering. Variasie in die parameters is beskryf met gepaste statistiese verdelings voorgestel deur verskeie literatuur (Holicky, 2009:199; JCSS, 2000). Aangaande die staal sterkte, is die gemiddelde waardes en standaardafwykings verkry deur standaard trek toetse terwyl die gemiddelde waardes en standaardafwykings van die plaat dikte en skroef diameter verkry is deur die bogenoemde metings.

Large span timber trusses are usually built with glulam. One problem with large span glulam trusses is that the connections needed to transfer the load between truss members are often complex and expensive. Another issue is transportation. Building large span trusses out of structural timber instead, could be a way of simplifying the connections and at the same time increase the degree of on-site construction and thereby solving the transportation problem.In this study, a total of 18 laboratory tests were performed with the purpose of investigating the tensile strength and the load slip behavior of different connection designs for large span structural timber trusses. Six different test groups corresponding to six different connection designs were tested. The materials used include members made of C24 timber and gusset plates made of birch plywood, aluminum, and steel. Screws were used as fasteners for five test groups and adhesive was used for one group. The influence of different reinforcement techniques including reinforcement screws and added aluminum sheets was studied.The results showed a ductile failure behavior for all test groups except for the group where adhesive was used. However, a decrease of ductility was observed for groups were aluminum sheets were used on the outsides of the mid placed plywood gusset plate. A 12-17 % increase in capacity was observed due to the presence of aluminum sheets. The reinforcement screws had no significant effect on the capacity. However, the presence of reinforcement screws did lead to a reduction in scatter both regarding capacity and stiffness.

The dissertation investigates the behaviour of timber-concrete connections with inclined screws – the load carrying capacity and deformability. The essen¬tial objects of investigation are the load carrying capacity of inclined screws; the modules of connection slip deformation, and the mechanical properties of mate¬rials and ware of which the connection is made. The load-carrying capacity of the connection depends on the properties of the material of connected member and the connectors, on which depends the strength and stiffness of the composite member. The main aim of dissertation is to create the connection load carrying capacity predicting model, based on the more realistic behaviour of the material of connected members; to prepare the simplified approach for load-carrying capacity predicting model for composite timber-concrete connections within at any angle in respect to timber grain in¬clined crews. The paper approaches a few major tasks such as the choice of suitable load-carrying capacity predicting base model; preparing it to composite timber-con¬crete connections with inclined screws; the experimental investigation of con¬nection with inclined screws under long- and short term loading; the experi¬mental investigation of properties of connected materials and type of used con¬nectors; the evaluation of created predictive model based on results also of other researchers experimental investigations.
Disertacijoje nagrinėjama kompozitinės medinės-betoninės jungties su įžambiai šlyties plokštumai orientuotais medsraigčiais elgsena – laikomoji galia ir deformacinės savybės. Pagrindiniai tyrimų objektai yra įžambiai medienos pluoštui orientuotų medsraigčių laikomoji galia, slinkties deformacijų moduliai ir mechaninės jungtį sudarančių elementų savybės, veikiančios jungties elgseną. Nuo medsraigčio ašies posvyrio kampo, deformacinių po medsraigčiu glemžiamos ir ištraukiamos medienos ir lenkiamo medsraigčio savybių priklauso ir jungties irties pobūdis, laikomoji galia ir slinkties deformacijų moduliai, o nuo pastarųjų – kompozitinio elemento stiprumas ir standumas. Pagrindinis disertacijos tikslas yra sukurti skaičiavimo modelį tokių jungčių laikomajai galiai nuspėti, kuo tiksliau atsižvelgiant į medžiagų ir elementų mechanines savybes; pateikti supaprastintą skaičiuojamąjį modelį, skirtą bet kokiu kampu medienos pluošto atžvilgiu įsriegtų medsraigčių laikomajai galiai nuspėti. Darbe sprendžiami keli pagrindiniai uždaviniai: tinkamo pamatinio jungties laikomąją galią vertinančio skaičiuojamojo modelio parinkimas, jo pritaikymas įžambiai medienos pluoštui orientuotiems medsraigčiams; trumpalaikis ir ilgalaikis eksperimentinis įžambinės medsraigtinės jungties laikomosios galios tyrimas ir vertinimas; kitų autorių eksperimentinių rezultatų vertinimas sukurtajam jungties laikomąją galią vertinančiam modeliui pagrįsti.

Submitted by RAFAEL AGUERA REZENO DA SILVA null (aguera.feg@gmail.com) on 2016-04-10T23:05:59Z No. of bitstreams: 1 Dissertação_Aguera.pdf: 5287076 bytes, checksum: 018a793b7d2956814528ec0cb549cc66 (MD5)
Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-04-12T17:53:04Z (GMT) No. of bitstreams: 1 silva_rar_me_guara.pdf: 5287076 bytes, checksum: 018a793b7d2956814528ec0cb549cc66 (MD5)
Made available in DSpace on 2016-04-12T17:53:04Z (GMT). No. of bitstreams: 1 silva_rar_me_guara.pdf: 5287076 bytes, checksum: 018a793b7d2956814528ec0cb549cc66 (MD5) Previous issue date: 2016-02-16
Em bielas automotivas, os parafusos atuam de maneira a manter a união entre capa e haste, suportando as cargas trativas, compressivas e transversais originadas no olhal maior. Para tais componentes, o dimensionamento de juntas aparafusadas torna-se complexo, visto que a disposição dos parafusos e a geometria do mancal conduzem ao surgimento de esforços excêntricos à face de fratura, elevando a criticidade do projeto. Em vista disso, e do reduzido número de publicações sobre o assunto, o presente trabalho propôs uma “abordagem híbrida” para a análise de juntas aparafusadas em bielas anguladas, utilizando resultados obtidos a partir de um modelo de elementos finitos simplificado e as ferramentas contidas no roteiro VDI 2230 parte 1. Além disso, foi avaliada a influência do fenômeno de abertura unilateral sobre a vida em fadiga dos fixadores utilizados em bielas anguladas, analisando os resultados obtidos de modo a desenvolver um critério de avaliação para a fadiga desses componentes. A despeito das restrições, a abordagem numérico-analítica desenvolvida demostrou-se atraente, tanto pelo baixo custo computacional associado, quanto por sua precisão, principalmente na determinação da força tensora residual mínima para a prevenção de abertura, mostrando-se adequado para processos de otimização multiparamétricos, selecionando designs promissores passíveis de posterior avaliação através de modelos refinados. Já as análises de influência do fenômeno abertura não apresentaram alterações sensíveis nos níveis de força adicional dos fixadores, fato esse relacionado com a posição dos pontos de abertura em relação ao parafuso e ao mancal. Apesar disso, as simulações realizadas demonstraram que as condições de carregamento avaliadas não influenciaram no diagrama de Haigh local dos nós críticos de cada fixador, o que sugere o uso de resultados extraídos de ensaios de fadiga como variáveis de entrada para simulações em juntas de bielas, incluindo assim as influências benéficas do processo de manufatura.
Connecting rods screws maintain the connection between cap and shank supporting the tensile, compressive and transversal loads applied on the big end. In this case, the design of bolted joints become complex since the screw’s position and bearing geometry lead to eccentric forces acting on the joint split line. Due to that and the reduced number of publications on the subject, this dissertation aims to develop a "hybrid approach" for the analysis of bolted joints in angled connecting rods, using results from a simplified finite element model as input for the VDI 2230 part 1 guideline. In addition to that, this study evaluates the influence of unilateral opening phenomenon on fasteners fatigue life, analyzing the results in order to develop a criterion for fatigue analysis of connecting rod bolts. Despite the restrictions, the “hybrid approach” proved to be attractive due to the low computational cost and accuracy, especially for the calculation of minimal residual tensile force to prevent opening, being suitable for multiparametric optimization during project early phases. The opening phenomenon showed no significant changes in fastener’s additional forces, fact related to the position of joint opening points. Nevertheless, the simulations showed that the loading conditions did not influence on the local Haigh diagram of critical nodes, which suggests the use of fasters fatigue tests as input variables for fatigue simulations, thus including the beneficial influences of the manufacturing process.

The aim of the thesis is to design a steel structure of the parking building in the center of Brno. The plan dimensions of the building are 29 x 77.5 m including a missing corner of the dimensions 5 x 12.5 m in the southeast part of the construction. The construction of the parking building has 4 above-ground floors with the same layout and the fifth floor situated only in the middle section of the construction. Each floor is 3.5 m high. The total height of the construction in the place of the roofed part of the fifth floor is 17.5 m, otherwise 14 m. A spatial frame is the main load-bearing part consisting of 7 fields in the longitudinal direction and 5 fields in the transversal direction. The spatial frame is formed of columns and longitudinal and transversal girders. Steel-concrete composite joists are pin-supported among longitudinal girders. The construction of the parking building is solved in three versions considering different placing of columns to the base structure and different placing of longitudinal and transversal girders to the columns. The resulting draft is worked out in details. Roof cladding will be made using sandwich panels and walls will be made out of glass panels. The calculation has been done in Scia Engineer 2014 program and by manual calculation.

The aim of my work is to describe high-voltage switchgear type UniGear 500R, which is part of UniGear switchgears family. I will focus on heating issue of one 500R unit and its parts during operation. Maximum values of this heating is limited by standards and can´t be exceed to ensure safe and reliable operation. That is why the heating tests are necessary part of designing and developing switchgears. Calculation will be made by two different ways. First is classic one-pole heating net method and second is numerical simulation in Solidworks flow simulation program. Except the theoretical description there will be presented also used 3D model and explanation of both method, used to calculation and simulation. Last point of this work is measuring of this type of switchgear and getting real data. The main point there is to compare measured values with values calculated and decide if is possible to simulate tests with appropriate accuracy. Then would be also possible to substitute the real test in laboratory, which costs many thousand crowns and takes lots hours of time. This work is collaborated with EJF division of ABB Company, where I am employed. Heating issues in this company is always on process, because of developing and improving of their products. So this work could be helpful in this field. ABB provides all materials needed, especially technical catalogues, 3D model and final values from laboratory measuring. Support from college faculty is mainly in study consultations and proposing of calculations making. In the end of work will be make final comparison and evaluation of achieved results.

O emprego de parafusos auto-atarraxantes em ligações metálicas, nos últimos anos, têm aumentado de forma significativa, principalmente como dispositivo de ligação entre componentes leves da construção metálica, como por exemplo, nas ligações entre telhas metálicas e terças. Tais ligações apresentam modos de falha diferentes dos observados para as ligações parafusadas convencionais, em função do tipo de parafuso e das reduzidas espessuras dos elementos conectados, definidos como \"pull-out\" e \"pull-over\". No Brasil, a carência de estudos específicos nesse tema foi uma das razões da omissão da recente norma brasileira de dimensionamento de estruturas de aço constituídas por perfis formados a frio - NBR 14762:2001, quanto a procedimentos específicos para o projeto de ligações com parafusos auto-atarraxantes. Nesse trabalho foi desenvolvido um estudo abrangente sobre as ligações metálicas com parafusos auto-atarraxantes, com ênfase na ligação telha-terça, onde são apresentados os procedimentos e as recomendações das principais normas estrangeiras, bem como os ensaios padronizados para caracterização dos parafusos e avaliação do comportamento estrutural e resistência de ligações. São apresentados também os resultados de uma investigação experimental, com base no ensaio padrão do AISI (1996) (American Iron and Steel Institute), em 27 corpos-de-prova com variação no diâmetro do parafuso e espessura dos componentes da ligação (terça e telha), com o objetivo principal de avaliar as expressões das AISI (2001b e 1996) para dimensionamento. Como conclusão, são relatadas as dificuldades associadas ao ensaio padrão, que apesar de sua concepção simples, conduz à elevada variabilidade nos resultados, indicando a necessidade da adoção de ensaios mais representativos e confiáveis.
The use of screws in steel connections has increased significantly in recent years, mainly as connecting devices between light-gage components in steel construction, as, for example, in joints between metal roofing and purlins. These connections exhibit different failure modes from those displayed by conventional bolted connections, due to the type of fastener and the reduced thicknesses of the connected elements, defined as pull-out and pull-over. In Brazil, the lack of specific studies of this theme was one of the reasons for the omission of specific procedures for the design of screw connections from the new edition of the brazilian code for cold-formed steel members - NBR 14762:2001. The work reported here involved a comprehensive study of steel connections using screws, with emphasis on the sheating-purlin connection. A presentation is made of the procedures and recommendations of the main foreign codes, as well as of standardized tests for characterizing screws and evaluating the structural behavior and strength of connections. Also presented are the results of an experimental investigation based on the standard test of the AISI (1996) (American Iron and Steel Institute) applied to 27 test specimens with varying screw diameters and connector component thicknesses (purlin and sheeting), whose main purpose was to evaluate the AISI\'s design equations (2001b e 1996). To conclude, a report is made of the difficulties associated with the standard test, which, despite its simple conception, leads to considerably variable results, indicating the need for the adoption of more representative and reliable tests.

Master’s thesis deal with commodities of metallurgical and connecting material in engineering firm. For these commodities is concocted an analysis of current statement, based on it will be designed its material standard. Purpose of this dissertation should be reaching of potential savings of money, time and increasing of productivity.

Disertacijoje nagrinėjama kompozitinės medinės-betoninės jungties su įžambiai šlyties plokštumai orientuotais medsraigčiais elgsena – laikomoji galia ir deformacinės savybės. Pagrindiniai tyrimų objektai yra įžambiai medienos pluoštui orientuotų medsraigčių laikomoji galia, slinkties deformacijų moduliai ir mechaninės jungtį sudarančių elementų savybės, veikiančios jungties elgseną. Nuo medsraigčio ašies posvyrio kampo, deformacinių po medsraigčiu glemžiamos ir ištraukiamos medienos ir lenkiamo medsraigčio savybių priklauso ir jungties irties pobūdis, laikomoji galia ir slinkties deformacijų moduliai, o nuo pastarųjų – kompozitinio elemento stiprumas ir standumas. Pagrindinis disertacijos tikslas yra sukurti skaičiavimo modelį tokių jungčių laikomajai galiai nuspėti, kuo tiksliau atsižvelgiant į medžiagų ir elementų mechanines savybes; pateikti supaprastintą skaičiuojamąjį modelį, skirtą bet kokiu kampu medienos pluošto atžvilgiu įsriegtų medsraigčių laikomajai galiai nuspėti. Darbe sprendžiami keli pagrindiniai uždaviniai: tinkamo pamatinio jungties laikomąją galią vertinančio skaičiuojamojo modelio parinkimas, jo pritaikymas įžambiai medienos pluoštui orientuotiems medsraigčiams; trumpalaikis ir ilgalaikis eksperimentinis įžambinės medsraigtinės jungties laikomosios galios tyrimas ir vertinimas; kitų autorių eksperimentinių rezultatų vertinimas sukurtajam jungties laikomąją galią vertinančiam modeliui pagrįsti.
The dissertation investigates the behaviour of timber-concrete connections with inclined screws – the load carrying capacity and deformability. The essen¬tial objects of investigation are the load carrying capacity of inclined screws; the modules of connection slip deformation, and the mechanical properties of mate¬rials and ware of which the connection is made. The load-carrying capacity of the connection depends on the properties of the material of connected member and the connectors, on which depends the strength and stiffness of the composite member. The main aim of dissertation is to create the connection load carrying capacity predicting model, based on the more realistic behaviour of the material of connected members; to prepare the simplified approach for load-carrying capacity predicting model for composite timber-concrete connections within at any angle in respect to timber grain in¬clined crews. The paper approaches a few major tasks such as the choice of suitable load-carrying capacity predicting base model; preparing it to composite timber-con¬crete connections with inclined screws; the experimental investigation of con¬nection with inclined screws under long- and short term loading; the experi¬mental investigation of properties of connected materials and type of used con¬nectors; the evaluation of created predictive model based on results also of other researchers experimental investigations.

This study consists of three self-standing parts, each dealing with a different aspect of design of composite steel-concrete flexural members. The first part deals with a new type of shear connection in composite joists. Composite steel-concrete flexural members have increasingly become popular in design and construction of floor systems, structural frames, and bridges. A particularly popular system features composite trusses (joists) that can span large lengths and provide empty web space for installation of typical utility conduits. One of the prominent problems with respect to composite joists has been the installation of welded shear connection due to demanding welding requirements and the need for significant welding equipment at the job site. This part of the study presents a new type of shear connection developed at Virginia Tech â standoff screws. Results of experimental and analytical research are presented, as well as the development of a recommended design methodology. The second part deals with reliability of composite beams. Constant research advances in the field of composite steel-concrete beam design have resulted in numerous enhancements and changes to the American design practice, embodied in the composite construction provisions of the AISC Specification (AISC 1999). Results of a comprehensive reliability study of composite beams are presented. The study considers specification changes since the original reliability study by Galambos et al. (1976), considers a larger database of experimental data, and analyses recent proposals for changes in design of shear connection. Comparison of three different design methods is presented based on a study of 15,064 composite beam cases. A method to consider effect of degree of shear connection on strength reduction factor is proposed. Finally, while basic analysis theories between the two are similar, requirements for determining the strength of composite beams in Eurocode 4 (CEN 1992) and 1999 AISC Specification (AISC 1999) differ in many respects. This is particularly true when considering the design of shear connections. This part of the dissertation explores those differences through a comparative step-by-step discussion of major design aspects, and accompanying numerical example. Several shortcomings of 1999 AISC Specification are identified and adjustments proposed.
Ph. D.

碩士
國立陽明大學
生物醫學工程學系
103
Most of the multi-stage implant system structure divided into abutment and implant component. Both abutment and implant structure are locked by abutment screw. Locking two-stage implant system structure by torque value of the manufacturers recommends. Because various manufacturers design, materials and processing, etc. Resulting in various torque values of abutment screw. However, the recommend torque of abutment combine implant is unclear. In addition, lower torque values of implant system and repeatedly chew of the mouth cause screw loosening made dental implant fracture. Furthermore, high torque values of implant system generate more high stiffness, leading to abutment thread abrasion and deformation or fracture. Effect of cyclic loading and fracture mode on the abutment screw with different torque of the multi-stage implant system. Two-stage implant system and three-stage implant carried out the maximum torque experiment, and then, it got maximum torque value that converted into percentage of torque value, then decreasing 10% torque value and increasing 10% torque value, converted into low limit of recommend torque, recommend torque and high limit of recommend torque. Subsequent, each two-stage implant system groups using a test according to ISO 14801 static / dynamic tests. It research that static load value and fatigue strength. Finally, After the experiment specimen analysis failure mode by the all test process. Each the maximum static load and the fatigue strength of two-stage implant system increases as locking torque value increases trends as well. Mode of failure of two-stage and three stage implant system are concentrated in abutment and implant connection.

Im Projekt wurden lösbare Verbindungstechniken für hochgefüllte Holz-Polymer-Werkstoffe für das statisch-dynamische Belastungskollektiv des Maschinenbaus erarbeitet. Im Fokus der Untersuchungen standen vorgespannte Schraubverbindungen in den konstruktiven Ausführungen als Durchsteckschraubverbindung und Einschraubverbindungen. Die Direktverschraubung und die Quergewindebolzen-Steckschraubverbindung wurden aus technisch-wirtschaftlicher Sicht für den Werkstoff als Sonderverfahren der Einschraubverbindung favorisiert. Für die benannten Verschraubungsarten wurden Montageempfehlungen, Grenzlastbereiche und Einflussfaktoren der Verbindungen unter Berücksichtigung des Werkstoffes erarbeitet. Abschließend wurden die erarbeiteten Kenntnisse zu lösbaren Verbindungstechniken auf einen Demonstrator in der Fördertechnik übertragen.
In the project removable connection methods for high filled wood polymer composites for static and dynamic loads were worked out. The focuses of studies were pre-stressed screw connections in a constructive style as push-through screw connection and screw in connection. On the basis of the material and the technical-economic reasons the 'direct-screw-connection' and 'cross-threaded bolt plug-in screw connection' were favored as a special method of the screw-in connection. Installation recommendations, limit load ranges and influencing factors of the connections based on the material were compiled for the named types of bolting. Finally the compiled knowledges of the removable connections were transferred into demonstrator for conveying systems.

Cold-formed steel connections are commonly fastened using self-tapping self-drilling screws. The behavior of these connections can differ based on the screw manufacturer or the cold-formed steel product used, both of which have a large selection available for use in industry. Because of their popularity and the many possible variations of these connections, researchers have frequently tested screw connections to characterize their behavior. However, repeatedly conducting this type of experiment is time consuming and expensive. Therefore, the purpose of this work was to create finite element models that can successfully predict the behavior of single lap shear screw connections, a common connection type used in cold-formed steel framing. These models were created using the finite element program Abaqus/CAE. To validate these models, test results from Pham and Moen (2015) were used to compare the stiffness, strength, and failure mode of multiple connections. A parametric study is also conducted to determine the influence of contact parameters on the behavior of the model. The results showed that all models consistently had good agreement with the connection stiffness and that most of the models also had good agreement with the peak load and failure mode of the v tests. These results were also compared to the design equations available for screw connections from the American Iron and Steel Institute (AISI). This comparison revealed that the models are more successful at predicting screw connection behavior than AISI, and thus work is required to improve the accuracy of AISI’s design equations. The eventual goal of this work is to develop a procedure to build and validate models without requiring test data. This work continuing in the future can lead to recommendations to improve AISI’s design equations and to implement the behavior of the connections into large cold-formed steel framing models such as diaphragms or shear walls.

碩士
國立雲林科技大學
營建工程系碩士班
94
This paper presents cyclic responses of six reinforced concrete exterior beam-to-column connections, namely, three pairs of concentric or eccentric connections. Specimen variables are joint eccentricity and anchorage of the beam bars terminating within the joint. One pair of connections used the standard 90-degree hooks anchored within the joint. The other two pairs of connections used headed reinforcement consisting of screw-deformed bars and mechanical anchorage devices. All six specimens exhibited beam yielding in the 1.5% drift cycle, developed an anticipated beam plastic hinge in subsequent cycles, and eventually reached the joint shear capacity at a drift level of 4% or more. Each eccentric connection performed worse than each companion concentric connection. Using headed bars with single mechanical device provided anchorage as good as using standard hooks. For specimens with single mechanical device, pushout spalling of the concrete covers behind the heads appeared after 5% drift level, which is considered to be acceptable. Specimens with double mechanical devices had no pushout spalling and better seismic performance than companion connections.

碩士
國立屏東科技大學
森林系
91
Knock-down（KD）furniture plays a very important role current time in both Taiwan and overseas market, and the designer and manufacturer also try to develop and improve the connecting screws used in the KD furniture products to meet their purposes .The furniture manufacturers generally use the connecting screw according to their experience only, because the structural performance data of connectors are limited. This study is trying to provide the furniture designer and manufacturer some suitable methods and data for reference to improve the connecting screws performance based on the guideline of hole diameter, the type of the screws, the spacing of screws and the allowable number of assembly. The results are as following: For the lumber core plywood, the withdrawal resistance on the flat face of panels is 22.5% higher than that on the edge faces, and on the end faces is only 83% of that of the edge faces. For particleboard, the withdrawal resistance on the flat face of panels is 68% higher than that on the end faces. For fiberboard, the withdrawal resistance on the flat face of panels is 61% higher than that on the end faces. The withdrawal resistance of connecting screws for fiberboard is the highest, then the particleboard, and the lumber core plywood is only 69%~78% of that for the fiberboard. The adequate pilot hole diameter on the flat face of panels is 70% (4.8mm) of the diameter of connecting screw, and 75% (5.8mm) of the diameter of connecting screw is suitable used on the edge faces of the panels. The withdrawal resistance of single threaded connecting screw is higher than that of Hi-Lo threaded connecting screw, regardless used in any position of panels. There are significant difference of bending moment resistance among connecting screw spacings on the different joints of wooden timber. It is increased for particleboard and fiberboard as the connecting screws spacing is increased. The maximum bending moment resistance of lumber core plywood with in-plane joint is reached under the spacing of 64mm. For the out-of plane joints, the spacing will be 96mm to reach the maximum bending moment resistance. There are no significant difference of withdrawal resistance for particleboard joints using connecting screws with by the number of assembly. The withdrawal resistance of connecting screws for the lumber core plywood and particleboard joints assembled 10 times is about 32% higher than that of assembled 15 to 20 times.

PhD thesis in Steel and Composite Construction submitted to the Faculty of Sciences and Technology of the University of Coimbra
Lightweight Steel Framing (LSF) construction is recognized as a sustainable construction system, not only because steel is one of the most recyclable materials in the world but also due to the advantages of this type of construction. The panelised method is one of the construction processes of pre-fabrication of walls, floors and roofs. These panels, which are produced in factory, are constituted by steel profiles and oriented strand boards (OSB) connected by screws, and then transported and assembled at the construction site. Screw connections fit perfectly in the industrialized production and they are highly used due to its efficiency, fast application and suitability for load bearing. Although the screws are easy to install, it is exceedingly difficult to quantify their stiffness and strength contributions to the structural system due to their complex behaviour. Moreover, the contribution from the OSB panels is usually omitted in the LSF structure design as structural element. Finally, the panelised method is one of the fastest and most efficient methods for LSF modular construction. However, due to the low mass of the construction elements and the high number of thermal bridges, one of the drawbacks of this construction system is having low thermal inertia. Over the years new technologies have been developed to increase buildings thermal inertia, such as Earth-to-Air Heat Exchangers (EAHE) and Trombe Walls. Although EAHE system are already well known, its design is always difficult to carry out due to the high variation of physical, thermal and geometric parameters. On the other hand, the application of the Trombe Walls in a LSF modular construction system has not yet been developed. In this context, the main objectives of this thesis are: (1) to analyse and give better understanding of screw connection in LSF panels and to analyse the contribution of OSB boards to the lateral stiffness of the steel frame; (2) to provide design guidelines for suitable design, and operation control, of an efficient EAHE; (3) to develop a new Trombe Wall system that can be easily assembled in a LSF construction. Therefore, this thesis is divided into four parts, where the first one is introductory and the remaining three are dedicated to the development of the aforementioned objectives. The first part of this thesis presents some structural concepts and discusses the thermal performance of LSF buildings focusing on thermal inertia. The mechanical and thermal properties of structural and non-structural materials are experimentally evaluated. To provide deeper understanding of screw connections in LSF structures and their impact on the response of the structure, the second part of this thesis presents experimental, numerical and analytical studies on screw connections (steel-to-steel and steel-to-OSB) and wall panels. Therefore, the main objectives of these part are: (i) to analyse the behaviour of steel-to-steel screw connections using experimental, numerical and analytical approaches (EN 1993-1-3 and AISI S100); (ii) to investigate experimentally the steel-to-OSB boards connection and to assess analytically their behaviour using formulae proposed by EN 1995-1-1 (2004); (iii) to characterize the behaviour of LSF panels using screw connections subjected to lateral loading and to analyse the OSB contribution; (iv) to develop a reliable numerical model for a parametric study in which the performance of the unbraced panel frame, OSB braced panel frame and panel frame braced using diagonal steel strips is compared. An extensive study on EAHE systems is presented in the third part of the thesis. The main research goals are: (i) to analyse the ground temperature variation with depth using analytical and experimental approaches; (ii) to develop a simple steady-state one-dimensional model for design and for prediction of the overall thermal performance of the system; (iii) to investigate the thermal performance of an EAHE system pilot installation located in Coimbra, during all four seasons of the year; (iv) to understand the influence of the system automation control; (v) to analyse the geometric (pipe diameter and length) and physical/thermal parameters (air velocity, pipe and ground thermal conductivity) and their impact on the thermal performance of the system; (vi) to analyse the influence of pipe spacing and diameter, and air velocity in transient conditions using Computational Fluid Dynamics (CFD) software (Ansys CFX 18.0). The fourth part of the thesis is fully dedicated to the development of a Water Trombe Wall that can be assembled in a LSF modular construction. The development of this system is divided in four parts: (i) to analyse the Thermal Energy Storage (TES) wall during four seasons of the year by means of experimental, analytical and numerical approaches; (ii) a parametric study where the influence of orientation, colour and thermal capacity of the TES are investigated; (iii) to analyse the influence of promoting heat exchanges between TES assemble on different façades using CFD modelling; (iv) to experimentally evaluate the thermal performance of a full-scale WTW prototype in a LSF construction located in Coimbra. Finally, the last chapter of this thesis presents the main conclusions of this work and a few recommendations for the future researches. RESUMO: A construção leve em aço (LSF, do inglês Lightweight Steel Framing) é atualmente reconhecida como um sistema construtivo sustentável, não só porque o aço é um dos materiais mais recicláveis do mundo, mas também devido às vantagens deste sistema construtivo. Um dos processos de pré-fabricação de paredes, lajes ou coberturas é a utilização do método construtivo da painelização. Neste método, painéis constituídos por perfis metálicos e placas de OSB (do inglês Oriented Strand Board) conectados através de parafusos, são construídos e montados em fábrica e depois transportados e assemblados em obra. A utilização de ligações aparafusadas demonstram ser as mais adequadas e eficientes garantindo maior resistência mecânica. O efeito das ligações aparafusadas no sistema estrutural é difícil de quantificar, devido à complexidade do comportamento dos parafusos. Além disso, a contribuição das placas de OSB na rigidez dos painéis é usualmente desprezado durante a fase de projeto. O método da painelização é considerado um dos métodos mais rápidos e eficazes da construção modular em LSF. No entanto, devido à reduzida massa dos elementos construtivos e ao elevado número de pontes térmicas, estas construções apresentam o inconveniente de ter uma baixa inércia térmica. Já existem várias tecnologias capazes de colmatar a baixa inércia térmica, tais como a utilização de sistemas EAHE (do inglês, Earth-to-Air Heat Exchangers) e as paredes de Trombe. Apesar dos sistemas EAHE já estarem bem presentes no mercado, o seu dimensionamento é sempre difícil de realizar/prever devido à enorme variação dos parâmetros físicos, térmicos e geométricos. Em relação às paredes de Trombe, a sua aplicação específica em uma construção modular em LSF ainda não foi desenvolvida. Neste contexto, os principais objetivos desta tese são: (1) avaliar o comportamento das ligações aparafusadas em painéis LSF e verificar a influência do OSB na rigidez dos painéis; (2) fornecer informações de dimensionamento e desempenho térmico de um sistema EAHE, (3) desenvolvimento um sistema de parede de Trombe que possa ser aplicado numa construção em LSF. Esta tese é dividida em quatro partes. Após a primeira parte, que é introdutória, as três restantes partes são dedicadas ao desenvolvimento dos objetivos acima indicados. Assim primeira parte da tese apresenta uma visão geral da construção modular a nível estrutural e térmico. É também apresentado um estudo experimental da caracterização mecânica e térmica de alguns materiais utilizados em construção LSF. De forma a permitir uma melhor compreensão do comportamento das ligações aparafusadas e o seu impacto na estrutura, a segunda parte da tese apresenta estudos experimentais, numéricos e analíticos realizados em ligações aparafusadas (aço-açoe aço-OSB) e em painéis em LSF. Os objetivos principais da segunda parte são os seguintes: (i) avaliar o comportamento de ligações do tipo aço-aço através de modelos experimentais, numéricos e analíticos (EN 1993-1-3 e AISI S100); (ii) avaliar experimentalmente o comportamento de ligações do tipo aço-OSB e comparar com o modelo analítico da EN 1995-1-1 (2004); (iii) avaliar experimentalmente o comportamento de painéis em LSF quando sujeitos a uma carga horizontal e verificar qual a contribuição do OSB e das ligações aparafusadas na sua desempenho estrutural; (iv) desenvolver um modelo numérico calibrado e validado com base em dados experimentais que será utilizado para comparar a contribuição do OSB com a utilização de uma fita metálica de contraventamento estrutural. Na terceira parte da tese é apresentado um estudo sobre sistemas EAHE. As principais linhas de investigação são: (i) avaliar a temperatura do solo em profundidade; (ii) desenvolvimento de método analítico unidimensional e estacionário que possa ser utilizado para dimensionamento e previsão, em evolução transiente hora-a-hora, do desempenho térmico de um sistema EAHE; (iii) avaliar o desempenho térmico de um sistema EAHE instalado num edifício, localizado em Coimbra, durante quatro estações do ano; (iv) análise do controlo domótico do sistema; (vi) avaliação analítica da influência dos parâmetros geométricos (diâmetro, comprimento de tubos) e físicos/térmicos (velocidade do ar, condutividade térmica dos tubos e do solo); (vii) verificar a influência da distância entre tubos, diâmetro e velocidade do ar em regime transiente através de modelação CFD (do inglês, Computacional Fluid Dynamics) em ANSYS CFX 18.0. A quarta parte da tese é dedica ao desenvolvimento de um sistema de parede de Trombe com água (WTW do inglês Water Trombe Wall) que possa ser integrado numa construção modular em LSF. O desenvolvimento do sistema é realizados em várias fases: (i) estudo experimental, analítico e numérico do acumulador de energia térmica durante as quatro estações do ano; (ii) estudo paramétrico do acumulador de energia térmica, onde é avaliada a sua orientação, cor e capacidade térmica; (iii) avaliação numérica (CFD) de permutação de calor entre painéis colocados em diferentes fachadas; (iv) avaliação experimental do desempenho térmico do protótipo WTW numa construção em LSF situada em Coimbra (Portugal). No capitulo final são apresentadas as principais conclusões do trabalho e recomendações para trabalhos futuros.
Cool-Haven; Urbimagem; Fachaimper; Forbo flooring systems; Weber (Saint-Gobain); Termolan; Bifase, Sociveda, Falper e FibroPlac.