The diploma thesis is focused on the comparison of the linear and nonlinear analysis of the steel structure and the resulting differences in both the numerical results and the time needed to obtain these results These analyzes are performed on a high-rise building, which has 10 floors and is used as an administrative building. Static model construction and calculations are performed in software system from Dlubal RFEM only loads for individual load cases are calculated manually.

This thesis focuses on the design and assessment of the supporting steel structure of departures hall for international airport Pardubice. The design is processed in two variants, one of which is selected and further elaborated. The hall contains one-story built for office and comercial use. To obtain the internal forces in the structure, modelling of the hall in the FEM computermodeling software was selected. The thesis includes manual assessment of selected elements and details, the assessment of elements in computational software, drawings and bill of material.

In this work is presented development of computational model of real timber truss in collapse state. The model was solved linearly and geometrically non-linearly and the results were evaluated. The aim was to depict the real behavior of the structure.

The thesis is focused on the investigation of Rayleigh-Bénard problem in an extended setting approximating the conditions in the Earth's mantle. The aim is to evaluate the influence of depth- and temperature- dependent material parameters, dissipation, adiabatic heating/cooling and heat sources on the qualitative characteristics of thermal convection. We identify the critical values of dimensionless parameters that determine the onset of convection and characterize the dominating convection patterns in marginally supercritical states. These issues are addressed by the application of linear stability analysis and weakly non-linear analysis. It has been found that the character of convection differ substantially from the standard case of Rayleigh-Bénard convection. Powered by TCPDF (www.tcpdf.org)

Studiens syfte är att undersöka expressiv fonologisk förmåga hos barn i åldrarna 3;5-4;9 år som följer en atypisk tal- och språkutveckling och jämföra den med en åldersmatchad kontrollgrupp.  Ytterligare ett syfte är att undersöka huruvida det föreligger ett samband mellan expressiv fonologisk förmåga och impressiv lexikal förmåga. Elva barn med konstaterade uttalssvårigheter rekryterades från logopedmottagningar och språkförskolor i Stockholm och i Östergötland. Barnen testades i en för dem välkänd miljö med bedömningsmaterialet LINUS. Barnens svar audioinspelades och transkriberades och utifrån transkriptionerna gjordes en analys med utgångspunkt från icke-linjär fonologi samt beräkning av Percentage Phonemes Correct och Word Complexity Measure. Resultatet jämfördes sedan med kontrollgruppen. Åtta av barnen i studiegruppen testades även med PPVT-IV för att undersöka eventuella samband mellan expressiv fonologisk förmåga och impressiv lexikal förmåga. Resultatet visade att barnen i de båda grupperna uppvisade uttalsavvikelser från vuxet målordsuttal på ord-, stavelse och segmentnivå, stavelsenivån var den nivå där flest avvikelser förekom i båda grupperna, men att avvikelserna förekom i högre grad hos barnen i studiegruppen. På stavelse- och segmentnivå kunde signifikanta skillnader ses men inte på ordnivå mellan grupperna. På stavelsenivå förekom klusterreduktioner i större utsträckning än uteslutning av enskilda segment för båda grupperna. På segmentnivå uppvisade barnen i studiegruppen problem med samtliga särdrag (sätt, plats och ton), till skillnad från barnen i kontrollgruppen som endast uppvisade problem med särdraget plats. Barnen i studiegruppen fick lägre värden på såväl PPC och WCM. En signifikant skillnad sågs mellan PPC och WCM i studiegruppen men inte i kontrollgruppen. Inget samband mellan expressiv fonologisk förmåga och impressiv lexikal förmåga kunde påvisas i följande studie. Studiens resultat indikerar att det är viktigt att ta hänsyn till alla fonologiska nivåer vid en bedömning och resultatet motiverar att ett icke-linjärt perspektiv kan vara till fördel vid planering av intervention. Då stavelsenivån ger upphov till störst svårigheter är det viktigt att ta hänsyn till detta vid fonologisk intervention. Studiens resultat kan ligga till grund för hur en icke-linjär analys kan användas inom klinisk verksamhet. / The aim of the study is to investigate the expressive phonological ability in children aged 3;5-4;9 following an atypical speech and language development and make a comparison to an age-matched control group following a typical speech and language development. A further purpose is to investigate whether there is a relation between expressive phonological ability and receptive lexical ability. Eleven children with speech sound difficulties were recruited from Speech-Language Pathology clinics and preschool language units in Stockholm and Östergötland. The children were tested in a familiar environment, with the swedish phonological assessment material LINUS. The children's responses were audio-recorded and transcribed and based on the transcriptions, a non-linear phonology analysis and calculations of Percentage Phonemes Correct and Word Complexity Measure were made. The results were then compared to the control group. Eight of the children were also tested with PPVT-IV to investigate a possible correlation between expressive phonological ability and receptive lexical ability. The results showed that the children in both groups had deviations at word-, syllable- and segmental levels, the syllable level appeared to be the most affected level in both groups, but that the deviations were more frequent in the study group. The differences on syllable- and segmental levels were significant, whereas the difference at word level was not significant between the groups. At the level of syllable, cluster reductions occurred to a greater extent than the exclusion of individual segments for both groups. At the segmental level, the study group showed problems with all features (manner, place and tone), whereas the children in the control group only had problems with the feature place. The study group had lower PPC and WCM than the control group. A significant difference was seen between PPC and WCM in the study group but not in the control group. No correlation between expressive phonological ability and receptive lexical ability was found. The results of the study indicate that it’s important to address all phonological levels in assessment and motivate that a non-linear approach could be beneficial as basis for planning of treatment. Since the syllable-level is the most affected it is important to address it in intervention. The report could serve as a guide for clinicians when applying a non-linear analysis.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23188号 / 工博第4832号 / 新制||工||1755(附属図書館) / 京都大学大学院工学研究科建築学専攻 / (主査)教授 松島 信一, 教授 竹脇 出, 教授 林 康裕 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

This dissertation introduces a general, predictive and cost-efficient reduced-order modeling (ROM) technique for characterization of flame response under acoustic modulation. The model is built upon the kinematic flame model–G-equation to describe the flame topology and dynamics, and the novelties of the ROM lie in i) a procedure to create the compatible base flow that can reproduce the correct flame geometry and ii) the use of a physically-consistent acoustic modulation field for the characterization of flame response. This ROM addresses the significant limitations of the classical kinematic model, which is only applicable to simple flame configurations and relies on ad-hoc models for the modulation field. The ROM is validated by considering the acoustically-excited premixed methane/air flames in conical and M-shape configurations. To test the model availability to practical burners, a confined flame configuration is also employed for model evaluation. Furthermore, to investigate the generality of the ROM to the burner flame, the performance of the ROM with respect to the V-shape and the swirled V-shape is investigated. The model accuracy is evaluated concerning flame geometrical features and flame describing function, and assessed by comparing the ROM results with both experimental measurements and direct- numerical-simulation results. It is found that the flame describing/transfer functions predicted by the ROM compare well with reference data, and are more accurate than those obtained from the conventional kinematic model built upon heuristically-presumed modulation fields.

Bifurcations in Huang's chaotic chemical reactor system leading from simple dynamics into chaotic regimes are considered. Following the linear stability analysis, the periodic orbit resulting from a Hopf bifurcation of any of the six fixed points is constructed analytically by the method of multiple scales across successively slower time scales, and its stability is then determined by the resulting final secularity condition. Furthermore, we run numerical simulations of our chemical reactor at a particular fixed point of interest, alongside a set of parameter values that forces our system to undergo Hopf bifurcation. These numerical simulations then verify our analysis of the normal form.

In Sweden, prefabrication in the construction industry is a very common system. In prefabricated structures, there are various kinds of connections and generally many hinged connections. Therefore, it is of high interest to study the behavior of the prefabricated buildings in relation to the connections. Two main theories that can be used to evaluate our structures are the non-linear finite element analysis (NLFEA) and the second order effects. These two theories help to study the real behavior of the structures. Software that can apply these two theories is the ATENA-GiD. Therefore, it was very interesting to explore this software and find out how it can be used for prefabricated buildings. For this reason, a simplified ten-storey building was studied which had been also used in Lindwall’s and Wester’s (2016) master thesis. Various cases were chosen for this building. The building was studied either with monolithic walls or with vertical slip connection between the prefabricated walls. Also, the hollow core (HC) slabs were modelled in two ways and the supports of the columns were modelled in three ways. Even when each slab was modelled with two materials (solid concrete for the upper and lower layer with smeared reinforcement for the lower layer and modified concrete in order to compensate for the voids), the increase in the time for analysis was not important. Also, the cracking was not extensive thanks to the relatively low wind load. The slip joint between the walls didn’t lead to the different displacement between the walls. It was found that the hinged support in the columns was modelled by using the upwind line of the base. In non-linear analysis cases, the model of the structure gave 20% larger displacements than in linear analysis cases which means that the cracking had an important influence on the second order effects despite that the cracking was not extensive. The reduction of the stiffness of the walls to 40% accounting for cracked sections in additional linear analyses to according to the Eurocode 2 was a conservative choice for this building. The most remarkable result was that when the supports of the columns were modelled with hinges there was smaller displacement than when the supports were fixed. The reason for this was the negative displacements due to the buckling of the columns of the first storey. Moreover, for the linear cases, there was a much smaller displacement (5mm) than Lindwall and Wester (2016) (17mm) and this was possibly due to the way that the hinges were modelled in my building. It is interesting to investigate other ways to model the hinges in ATENA-GiD as well as other ways to model the connections between the HC slabs and the perimetric beams. Also, the effect of creep through the modulus of elasticity could be analyzed. Finally, it would be interesting to include foundations in the model to study the possible need for anchorages.

Este trabalho apresenta desenvolvimentos na modelagem mecânica de estruturas de barras em concreto armado, bem como no acoplamento entre modelos de confiabilidade e otimização do tipo RBDO para obtenção de dimensões ótimas, respeitando os requisitos de segurança especificados em projeto. Quanto à modelagem mecânica via Método dos Elementos Finitos (MEF), além do comportamento não-linear geométrico e dos materiais, foi considerada a contribuição dos mecanismos complementares de resistência ao cisalhamento, dados pelo engrenamento de agregados e efeito de pino das armaduras longitudinais. Além disso, um modelo simplificado que avalia a contribuição da armadura transversal também foi proposto. Foi desenvolvida uma formulação de otimização que deixa a posição da linha neutra livre, ao contrário de formulações existentes. Esta formulação resultou em projetos mais economicos dos que aqueles encontrados na literatura. Na questão do acoplamento de confiabilidade e otimização, foram exploradas melhorias no Método de Superfície de Resposta e no acoplamento direto via Método de Confiabilidade de Primeira Ordem e Técnica dos Gradientes Numéricos. Estas resultaram em maior precisão dos resultados e aumento na velocidade de convergência. Os modelos mecânicos, incluindo análise não-linear e mecanismos complementares, a formulação de otimização e as técnicas de confiabilidade foram implementados em um programa computacional para dimensionamento ótimo de elementos em concreto armado. O programa foi utilizado na resolução de vários problemas-exemplo. Verificou-se que a consideração dos mecanismos complementares de resistência ao cisalhamento produziram acréscimo na carga última, quando comparadas com as respostas sem tais efeitos. Verificou-se também que os mesmos mecanismos produziram um aumento, até mais significativo, nos índices de confiabilidade obtidos. As dimensões ótimas de elementos estruturais também foram comparadas, considerando-se modelos lineares e não-lineares dos materiais. O estudo mostrou que os custos da estrutura otimizada são menores, quando se considera os efeitos de comportamento não-linear dos materiais. / This work presents some developments in the mechanical modeling of reinforced concrete bar structures, as well in the coupling of reliability and RBDO optimization models, with the purpose of obtaining optimal dimensions considering the safety requirements specified in design. As for the mechanical modeling via Finite Element Method (FEM), in addition to geometrical and material nonlinear behaviors, the contribution of shear resistance complementary mechanisms (aggregate interlock and dowel action of longitudinal reinforcement) was taken into account. Moreover, a simplified model that evaluates the contribution of shear reinforcement was also proposed. In an improvement of existing formulations, an optimization scheme was developed which leaves the position of the neutral axis free. This improvement resulted in more economical cross-sections, than those found in the literature. With respect to the coupling of reliability and optimization methods, improvements were sought in the Response Surface Method and in the direct coupling via First Order Reliability and Numerical Gradients methods. These improvements resulted in greater precision and in increased convergence speed. The mechanical models, including non linear effects and complementary mechanisms , the optimization and reliability formulations were implemented in a computational code for the optimum design of reinforced concrete structures. The program was used to solve a number of example problems. It was found that the complementary mechanisms resulted in an increase of ultimate loads, when compared to the response obtained without these effects. These mechanisms also resulted in an even greater increase of the elements reliability. Optimal dimensions of the structural elements were also compared, considering linear and non-linear material models. The cost of the optimum structure was found to be smaller when non linear effects are taken into account.