A nonlinear finite element analysis was performed for an existing road bridge in order to see if that could show a higher load bearing capacity, as an alternative to repairing or replacing. The regular linear analysis had shown that the bridge could not take any traffic load due to the effects from large and uneven support settlements. It is a five-span reinforced concrete bridge with a continuous slab on supports made out of rows of columns. The width-to-span ratio was around 1 and the supports were angled up to about 30°, giving rise to a complex three-dimensional behaviour, which was seen and studied in the nonlinear results. Since the bending moment was the limiting factor, the nonlinear analysis focused on that. The direct result was that the load bearing capacity was 730 kN for the traffic vehicle boogie load, B, in the ultimate limit state. This was however only for the load case tested, and several more disadvantageous vehicle positions may exist. Other aspects also became limiting, as the maximum allowed vertical deflection in the serviceability limit state was reached at 457 kN. The most restraining though, was the shear capacity from the linear analysis; 78 kN, since it was not possible to simulate that type of failure with the shell elements used in the nonlinear finite element analysis. The main aim of the thesis was nonetheless reached, since the nonlinear analysis was able to show a significant increase in load bearing capacity. A comparison was made with the settlements for the nonlinear case, to see how much influence they had on the load bearing capacity for traffic load. This was performed for both the bridge and a simple two-span beam. Both showed that there was no effect on the load bearing capacity in the ultimate limit. One thing to note was that the full settlements were applied, and with no relaxation due to creep. Another aim of the thesis was to make comments on the practical usability of the nonlinear finite element method in load bearing capacity assessments. A linear analysis was performed before the nonlinear in order to be able to determine the load case to be used in the latter. This worked well, as the strengths of the two methods could then be utilized. Convergence problems were however encountered for the nonlinear when using the regular static solver. Due to this, the dynamic explicit calculation scheme was used instead, treating the case as quasi-static. This managed to produce enough usable results. It was concluded that the nonlinear finite element method is useable for assessment calculations, but that its strengths and weaknesses must be known in order to make it an efficient method.

This thesis discusses the application of Slab Coupled Optical Fiber Sensors (SCOS) in a railgun. The specific goal of these sensors is to create an electric field profile at a specific point in the gun as the armature passes. The thesis explores the theory that powers the railgun as well as the principles of the SCOS sensors. It also elaborates on the various noise sources found throughout the detection system and concludes with a summary of the various field tests that were performed throughout this project. There are many benefits to using a railgun over traditional weapons in the field. These benefits not only include both safety and cost, but also greater overall defense capabilities. Unfortunately, the velocity skin effect (VSE) causes the current railgun designs to have limited life span through wear on the rails. In order to develop superior railguns and railgun armatures, the accurate detection of the VSE through measuring the electric field is of great interest. We used a SCOS, a small directionally precise dielectric sensor, as a small sensing area is required to be able to measure the electric fields inside of the rail gun. The actual usage of the SCOS within the railgun produced an additional set of problems that are not commonly encountered in the lab. The chief amongst these was noise from strain, RF pickup, and phase noise. This thesis also reports various methods used to reduce each of these noise sources.

En återkommande kritik när det kommer till byggnader med trästomme, har att göra med de relativt stora bjälklagshöjderna som uppstår till följd av träets egenskaper. Trots många fördelar i övrigt, måste bjälklag i trä vara avsevärt tjockare än motsvarande element i betong om de ska uppnå erforderlig styvhet, ljudisolering och brandteknisk prestanda. I detta arbete studeras aspekter som eventuellt kan optimera bjälklagsdimensioner för flerbostadshus med trästomme. Syftet med arbetet har varit att undersöka hur ett högre nyttjande av innerväggar som bärande, samt variation av bärriktningen för balkarna, kan påverka bjälklagshöjder och materialåtgång i bjälklag för flerbostadshus med trästomme. För att undersöka frågan har alternativa bjälklagskonstruktioner dimensionerat för tre befintliga flerbostadshus. För att kunna göra en rättvis jämförelse, har samma förutsättningar använts i samtliga fall vad beträffar bjälklagstyp och antaganden vid dimensionering. För att undersöka påverkan av ett högre nyttjande av innerväggar som bärande, har utgångspunkten varit ett befintligt flerbostadshus med trästomme (Byggnad A), där fyra alternativa bjälklagskonstruktioner dimensionerats. För två av alternativen har utgångspunkten varit byggnadens faktiska K-ritningar där samma bärande element som har nyttjats i det verkliga fallet har använts. De två alternativen har endast skilt sig med avseende på bärriktning. För de två återstående alternativen har utgångspunkten varit byggnadens A-ritningar. För fallen har ett fullt nyttjande av innerväggar som bärande nyttjats i konstruktionen. Alternativen har även i detta fall endast skilt sig med avseende på bärriktning. Frågan om balkriktningens påverkan har besvarats dels genom det ovan beskrivna fallet, dels genom att motsvarande dimensioneringar har utförts för två andra byggnader (Byggnad B och C). För dessa fall har flerbostadshusens stomutförande utgjorts av betong- samt kombinerad betong- och trästomme. För byggnaderna har två alternativa bjälklagskonstruktioner dimensionerats med ett fullt nyttjande av innerväggar som bärande. Skillnaden mellan alternativen har endast bestått i varierande bärriktning för balkarna. Vad beträffar ett högre nyttjande av innerväggar som bärande, har resultat erhållits ur analys av den befintliga träbyggnaden (Byggnad A). Resultaten visar att en besparing i bjälklagshöjd på 90 mm kan göras om innerväggar tillåts vara bärande, men endast för fallet där balkarna får löpa i byggnadens längdriktning. Lösningen leder även till en besparing av virke i bjälklaget på ca 26,3 % (balkåtgång) per våningsplan. Endast små skillnader uppstår om balkarna får löpa i byggnadens breddriktning, oavsett om fler innerväggar används som bärande eller inte. För balkriktningens påverkan har även de två återstående byggnaderna analyserats. För en av byggnaderna (Byggnad B) blir resultatet en 90 mm lägre bjälklagshöjd, samt en 28 % (balkåtgång) lägre virkesåtgång i bjälklaget per våningsplan, då balkarna löper i breddriktningen. För den tredje byggnaden (Byggnad C) leder olika balkriktningar inte till någon skillnad i bjälklagshöjd, och endast mycket små skillnader i virkesåtgång. Slutsatsen av studien är att för vissa byggnader kan bjälklagshöjd och materialåtgång i bjälklaget minskas om man beaktar bärriktningen för balkarna, detsamma gäller om man nyttjar fler innerväggar som bärande. Resultaten är dock specifika för de byggnader som använts, samt de förutsättningar som antagits i arbetet. Viss generalisering kan göras till flerbostadshus i allmänhet. / When considering slabs in wooden frame structure buildings, to achieve sufficient stiffness, soundproofing, and fire resistance in the structure, the wooden slabs must be significantly thicker than their concrete counterparts. This paper investigates the potential effect on slab height and total material use in the slab, when allowing for higher utilization of inner walls as load-bearing, while also considering the bearing direction of the beams. For the study, three existing multi-dwelling unit buildings have been subject to dimensioning of alternative slab constructions. To allow for a just comparison, a consistent approach has been kept when dimensioning the alternative constructions. One of the buildings (Building A) has been studied to compare a slab construction utilizing the actual number of bearing elements, with a construction utilizing a higher number of bearing elements by utilizing a higher number of inner walls. The results show a decrease in slab height by 90 mm, and in material use (beam volume) by 26,3 % per floor in favor of the alternative utilizing more bearing walls. However, this is only the case with the bearing direction of the beams spanning parallel to the length of the building. The two remaining buildings have been used to further study the effect of the bearing direction of the beams. The results show that for one of the buildings (Building B) there is a decrease in slab height by 90 mm and a decrease in material use by 28 % (beam volume) per floor in favor of the beams spanning parallel to the width of the building. For the third building (Building C), there is no difference in slab height and very little difference in material use.

Abstract A new generation of EN 1992-1-1 (2004) also known as Eurocode 2 is under development and currently there is a set of proposed provisions regarding section 6.4 about punching shear, PT1prEN 1992-1-1(2017). It was of interest to compare the proposal with the current punching shear design provisions. The aim of this master thesis was to compare the punching shear resistance obtained in accordance with both design codes. Furthermore the eect of some parameters on the resistance was to be compared. It was also of interest to evaluate the userfriendliness of the proposal. In order to meet the aim, a case study of a real 　at slab with drop panels was performed together with a parametric study of a pure ctive 　at slab. The parametric study was performed for inner, edge and corner columns in the cases prestressed, without and with shear reinforcement. It was concluded that the distance av from the column axis to the contra 　exural location has a big in　uence on the punching shear resistance. The factor ddg considering concrete type and aggregate properties also has a big impact on the resistance. The simplied estimation of av according to 6.4.3(2) in PT1prEN 1992-1-1 (2017) may be inaccurate in some cases. The length b0 of the control perimeter has a larger eect on the resistance in EN 1992-1-1 (2004) than in PT1prEN 1992-1-1 (2017). In PT1prEN 1992-1-1 (2017), studs located outside the second row has no impact on the resistance. The tensioning force in a prestressed 　at slab has a larger in　uence on the resistance in PT1prEN 1992-1-1 (2017) than in EN 1992-1-1 (2004). Furthermore, the reinforcement ratio is increased by the tendons, and thus aect the resistance in PT1prEN 1992-1-1 (2017). Clearer provisions for the denition of the support strip bs for corners and ends of walls are needed in PT1prEN 1992-1-1 (2017). It may be questionable if the reduction of the perimeter for a large supported area in accordance with 6.4.2(4) in PT1prEN 1992-1-1 (2017) underestimates the resistance v in some cases. Considering the work-load with PT1prEN 1992-1-1 (2017), more parameters are included. However, they may not require that much eort to obtain. Keywords: Punching shear, resistance, concrete, 　at slab, design provisions, Eurocode 2, case study, parametric study, shear reinforcement, prestressed vi

[pt] Este projeto de pesquisa propõe analisar formas de participação e apropriação da laje, inserida no contexto espacial da favela, e tendo como estudo de caso o bairro da Rocinha, na cidade do Rio de Janeiro, Brasil. A dissertação investiga conceitos que subvertem noções tradicionais de conceituação espacial, e como se dá a autogestão dos moradores no que concerne aspectos relacionados com o uso da laje. No tecido urbano densamente ocupado das favelas, este espaço nas moradias pode funcionar como interface de interseção entre os limites do espaço coletivo e privado. Foram, portanto, investigadas as ações e intervenções dos moradores na laje através de um enfoque na observação de abordagens socioculturais nesse ambiente. Reconhece-se na laje um tipo determinado de apropriação urbana, identificando-a como uma alternativa dos residentes à escassez de espaços públicos livres em favelas. Podemos observar que ela é usada como local de práticas vinculadas a processos de autoconstrução e ao aluguel, evidenciando aspectos relacionados ao valor de uso e de troca da laje. No caso da Rocinha, tanto em seu cotidiano como durante a pandemia de COVID-19, observamos manifestações coletivas na laje associadas à atividades sociais múltiplas. O processo de pesquisa de campo também revelou a laje vislumbrada sob a ótica do morador, como um espaço de projeção de sonho. Tornou-se aparente nestes processos sobretudo um caráter descrito na pesquisa como natureza híbrida. Foram definidas como técnicas de pesquisa: revisão de literatura; pesquisa etnográfica online qualitativa; e pesquisa de campo pela participação em encontros de coletivos. / [en] This research project proposes to analyze forms of participation and appropriation of the slab, inserted in the spatial context of the favela, and having as a case study the Rocinha neighborhood in the city of Rio de Janeiro, Brazil. The dissertation investigates concepts that subvert traditional notions of spatial conceptualization, and how the residents self-management occurs regarding aspects related to the use of the slab. In the densely occupied urban fabric of the slums, this space in the dwellings can function as an interface of intersection between the limits of collective and private space. Therefore, the actions and interventions of slum dwellers are investigated through a focus on the observation of sociocultural approaches in this environment. A particular type of urban appropriation is recognized in the slab, identifying it as an alternative of residents to the scarcity of free public spaces in slums. We can observe that it is used as a place for practices linked to self-construction and renting processes, showing aspects related to the use and exchange value of the slab. In the case of Rocinha, both in its daily life and during the pandemic of COVID-19, we observed collective manifestations on the slab associated with multiple social activities. The field research process also revealed the slab glimpsed from the perspective of the inhabitant, as a space of dream projection. It became apparent in these processes above all a character described in the research as hybrid nature. The research techniques defined were: literature review; qualitative online ethnographic research; and field research through participation in collective meetings.

Yes / The paper presents a technique to enhance the isolation between adjacent radiating elements which is common in densely packed antenna arrays. Such antennas provide frequency beam-scanning capability needed in Multiple-Input Multiple-Output (MIMO) systems and Synthetic Aperture Radars (SARs). The method proposed here uses a metamaterial decoupling slab (MTMDS), which is located between radiating elements, to suppress mutual-coupling between the elements that would otherwise degrade the antenna efficiency and performance in both the transmit and receive mode. The proposed MTM-DS consists of mirror imaged Eshaped slits engraved on a microstrip patch with inductive stub. Measured results confirm over 9–11 GHz with no MTM-DS the average isolation (S12) is -27 dB; however, with MTM-DS the average isolation improves to -38 dB. With this technique the separation between the radiating element can be reduced to 0.66λo, where λ0 is free space wavelength at 10 GHz. In addition, with this technique there is 15% improvement in operating bandwidth. At frequencies of high impedance match of 9.95 GHz and 10.63 GHz the gain is 4.52 dBi and 5.40 dBi, respectively. Furthermore, the technique eliminates poor front-to-back ratio encountered in other decoupling methods. MTM-DS is also relatively simple to implement. Assuming adequate space is available between adjacent radiators the MTM-DS can be fixed retrospectively on existing antenna arrays, which makes the proposed method versatile. / Partially supported by innovation programme under grant agreement H2020-MSCA-ITN-2016 SECRET- 722424 and the financial support from the UK Engineering and Physical Sciences Research Council (EPSRC) under grant EP/E022936/1.

Continuous casting represents 96% of all steel products made worldwide. To cast new alloys, optimal process parameters must be determined that reduce quality issues. Traditionally, this is a time-consuming and expensive process due to the need to run multiple casting trials. Alternatively, numerical models can be used to help guide development of optimal process parameters. In this thesis, a 3D thermal-solute-mechanical finite element model has been created using the THERCAST software to simulate the casting process of a new advanced high strength steel grade at Stelco’s Lake Erie Works facility. The model represents the caster from mould to exit, and takes into account heat transfer from the mould, sprays, rolls, and ambient air. The model has been extensively validated using plant measurements from steel shim trials and pyrometer data. The model is used to investigate the evolution of temperature and shell thickness along the cast length, and the effect of spray cooling and casting speed on the surface temperature at unbending to predict transverse cracking during secondary cooling. It was found that the susceptibility to cracking increased with lower casting speed and increased water spray cooling. Increasing the casting speed had a negligible effect, and it was found to decrease with decreasing water spray cooling. This decreased water spray cooling is also accompanied by an increase in metallurgical length, so further work is required to determine appropriate safety factors to ensure the steel is completely solidified. However, preliminary results of solute and mechanical models are also presented. Further work is required to improve the predictions made by these simulations. / Thesis / Master of Applied Science (MASc)

No description available.

No description available.

FEM program, program som använder finita element metoden, har en långhistoria av användning inom ingenjörsyrken. I modern tid har FEM programblivit en nödvändighet för beräkningar inte bara i byggbranchen, men ocksåinom andra ingenjörsverksamheter där stora mängder beräkningar krävs.Programmen har hjälpt ingenjörer att göra allt mer komplicerade beräkningarför projekt som inte bara tilltalar de av oss som är sakkunniga, utan också gerresultat som tilltalar de daglig användarna av projekt för vilka beräkningarnasom behövde göras för utformningen av projektet är mindre intressanta änarkitekturen och slutresultaten.Syftet med denna studie är att undersöka och jämföra modelleringen i två FEMprogram för att granska svagheterna och styrkorna som respektive program harsamt för att ge en grund för val av program i kvalitativa alternativt kvantitativastudier.I studien har analysobjektet, en plattramsbro som är en del av Umeåprojektetsom sammanlänkar motorvägen E12 norr om Ume älv med E4 motorvägensöder om Umeå, valts som objekt att analyseras i en komparativ studie med tvåFEM program, SOFiSTiK och Brigade/Standard. För att genomföra denna jämförelsemodelleras analysobjektet i båda programmen för att sedan genom attutföra laskombinationer erhålla de mest ogynsamma lasterna som kan tänkaskomma på bron i from av momentkrafter och tvärkrafter, och som bron behöverdimensionernas mot.Studien vissade att det finns ett samband mellan frihet och komplexitet i FEMprogram. Genom modelleringens gång kom det fram tydligt att automatiseringi form av moduler skapar ett resultat snabbare, men i utbyte begränsasanvändarens modelleringsfrihet när det kommer till att bygga upp egenskaperoch villkor från grunden.Studien kan grovt delas in bakgrund, lastförklaringar, modellering, analys ochslutsats. / FEM programs, programs that use the finite element method, have a longhistory of use within the engineering discipline. In modern times, FEMprograms have become a necessity for calculations not only in the constructionindustry, but also in other engineering branches where large amountsof calculations are required. The programs have helped engineers makeincreasingly complex calculations for projects that not only appeal to those whoare versed in the subject, but also provide results that appeal to the everydayusers of projects for whom the calculations that need to be made to shape theseprojects are less interesting than the architecture and the end results.The purpose of this study is to investigate and compare the modelling process intwo FEM programs in order to gauge the weaknesses and strengths that respectiveprogram brings, and to build a basis for election of FEM program in qualitativeand quantitative studies respectively.In the study, the analysis object, a slab frame bridge that is part of the Umeåproject that links the E12 highway north of the Ume River with the E4 motorwaysouth of Umeå, has been chosen as an object to be analyzed in a comparativestudy with two FEM programs, SOFiSTiK and Brigade/Standard. To do thiscomparative study the bridge will be modelled in both programs and then besubject to load combinations to find the most unfavorable load combinationsthat can occure on the bridge in the form of torque forces and transverse forcesare obtained. These loads will become the forces that the bridge will have toresist.The study showed that there is a connection between freedom and complexity inFEM programs. Through the modeling process, it became clear that automationin the form of modules creates a faster result, but in return the user’s freedomof modeling is limited when it comes to building properties and conditions fromthe ground up.The study can be roughly divided into background, explanations of load,modeling, analysis and conclusions.