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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Napěťová, deformační a bezpečnostní analýza statoru generátoru zatíženého nehomogenní teplotou / Stress, deformation and safety analysis of the generator stator loaded by nonhomogeneous temperature

Majdič, Petr January 2015 (has links)
This thesis deals with stress, strain and reliability analysis of synchronous generator stator including an inhomogeneous temperature field. Using the finite element method, stress and strain are calculated, and from these values safety against yield strength is determined, which is followed by the life calculation of the most stressed weld joint and the determination of its possible damage during the period required by the customer.
52

Návrh nosné konstrukce ŽB objektu garáží / RC load-bearing structure design of car park

Kudrna, Jan January 2016 (has links)
The diploma thesis deals with the design and assessment of reinforced concrete structure supporting two-storey building of the underground garage for cars. In the space above the garage is designed open area with public space. The project was designed especially outer water-impermeable construction method white bath and a base plate and a perimeter wall. The structure was designed as a comprehensive model. Computing analyzed by finite element method. All selected elements were assessed at the ultimate limit state and limit state, namely to limit state of cracking load and forced stress.
53

Estudo das vibrações induzidas por pedestres em passarelas de madeira / Study of pedestrian-induced vibrations on timber footbridges

Segundinho, Pedro Gutemberg de Alcântara 17 May 2010 (has links)
No Brasil, o estudo a respeito das vibrações induzidas por pedestres em passarelas vem sendo realizado a partir do início dos anos 1990, para passarelas de concreto e de aço. No entanto, ainda não há registro de estudos desse tipo e a norma brasileira NBR 7190 (1997) de projeto de estruturas de madeira apresenta somente critérios de dimensionamento para carregamentos estáticos, no caso de passarelas de madeira. Nesse contexto, este trabalho tem como objetivo geral a análise teórica, numérica e experimental de passarelas de madeira simplesmente apoiadas, com vistas a propor recomendações de projeto relacionadas ao conforto humano nessas estruturas. Este estudo foi desenvolvido a partir da análise de diretrizes normativas e critérios sugeridos por diversos autores, da análise teórica de passarelas dimensionadas segundo os critérios da NBR 7190 (1997), de modelos numéricos construídos em elementos finitos e de ensaios experimentais em modelo reduzido. Entre as conclusões alcançadas, destaca-se que a formulação de Euler-Bernoulli é adequada para o cálculo da primeira frequência natural nas direções transversal vertical e transversal horizontal em passarelas de madeira simplesmente apoiadas; entretanto, especial atenção deve ser dada para a avaliação da rigidez à flexão na direção transversal horizontal. Finalmente, sugeriu-se uma proposta para verificação do estado limite de serviço devido às vibrações induzidas por pedestres em passarelas de madeira simplesmente apoiadas, no tocante ao cálculo de frequências e acelerações, a ser inserida na futura revisão da norma brasileira de projeto de estruturas de madeira. / In Brazil, studies about pedestrian-induced vibrations on footbridges have been carried out since the early 1990s, for concrete and steel footbridges. However, there is no record of such studies and the brazilian standard NBR 7190 (1997) for the design of timber structures only presents design requirements for static loads, in the case of timber footbridges. Therefore, this paper aims to general theoretical analysis, numerical and experimental simply-supported beams timber footbridges, with a view to proposing recommendations for projects related to human comfort in these structures. This study was developed from the study of standards guidelines and criteria suggested by several authors, the theoretical analysis of footbridges design according to the criteria of the NBR 7190 (1997), numerical models using finite element and experimental tests on reduced model. Among the conclusions reached, it is emphasized that the formulation of Euler-Bernoulli is suitable for calculating the first natural frequency in vertical and lateral directions simply-supported beams timber footbridges; however, special attention should be given to the evaluation of lateral bending stiffness. Finally, we have suggested a proposal serviceability limit state verification due to pedestrian-induced vibrations on simply-supported beams timber footbridges, concerning the calculation of frequencies and accelerations to be included in a future review of the brazilian standard for the design of timber structures.
54

A Comparative Study Of Aisc-360 And Eurocode 3 Strength Limit States

Sahin, Serkan 01 September 2009 (has links) (PDF)
Nowadays / design, fabrication and erection of steel structures can be taken place at different locations as a result of rapid globalization / owners may require the use of widely accepted steel design codes. Therefore, engineers are faced with the challenge of being competent with several design specifications for a particular material type. AISC-360 and EC3 are widely accepted steel structure design specifications that utilize limit state principles with some similarities and differences in application. Hereby a study has been undertaken to put together the nominal strength expressions presented in both AISC-360 and EC3 codes in a single document, to identify the similarities and the differences in calculated strengths and to facilitate rapid learning of either of the specifications with prior knowledge of the other. Because of the wide scope of specifications, only fundamental failure modes are considered in this thesis. Resistance equations are directly compared with each other wherever possible. For cases where the treatment of specifications is entirely different, representative members were considered for comparison purposes.
55

Optimal design of mesostructured materials under uncertainty

Patel, Jiten 24 August 2009 (has links)
The main objective of the topology optimization is to fulfill the objective function with the minimum amount of material. This reduces the overall cost of the structure and at the same time reduces the assembly, manufacturing and maintenance costs because of the reduced number of parts in the final structure. The concept of reliability analysis can be incorporated into the deterministic topology optimization method; this incorporated scheme is referred to as Reliability-based Topology Optimization (RBTO). In RBTO, the statistical nature of constraints and design problems are defined in the objective function and probabilistic constraint. The probabilistic constraint can specify the required reliability level of the system. In practical applications, however, finding global optimum in the presence of uncertainty is a difficult and computationally intensive task, since for every possible design a full stochastic analysis has to be performed for estimating various statistical parameters. Efficient methodologies are therefore required for the solution of the stochastic part and the optimization part of the design process. This research will explore a reliability-based synthesis method which estimates all the statistical parameters and finds the optimum while being less computationally intensive. The efficiency of the proposed method is achieved with the combination of topology optimization and stochastic approximation which utilizes a sampling technique such as Latin Hypercube Sampling (LHS) and surrogate modeling techniques such as Local Regression and Classification using Artificial Neural Networks (ANN). Local regression is comparatively less computationally intensive and produces good results in case of low probability of failures whereas Classification is particularly useful in cases where the reliability of failure has to be estimated with disjoint failure domains. Because classification using ANN is comparatively more computationally demanding than Local regression, classification is only used when local regression fails to give the desired level of goodness of fit. Nevertheless, classification is an indispensible tool in estimating the probability of failure when the failure domain is discontinuous. Representative examples will be demonstrated where the method is used to design customized meso-scale truss structures and a macro-scale hydrogen storage tank. The final deliverable from this research will be a less computationally intensive and robust RBTO procedure that can be used for design of truss structures with variable design parameters and force and boundary conditions.
56

Cpt Based Compressibilty Assessment Of Soils

Ozkahriman, Fatma 01 July 2004 (has links) (PDF)
One of the most critical problems geotechnical engineers face with is the determination of the amount of consolidation settlement that will occur at a site as a result of the construction of a structure. The compressibility behavior of the soil is an important parameter in determining the amount of consolidation settlement. The goal of this study is to develop probabilistically based correlation between the compressibility behavior of soil and in-situ test data. Within the scope of this research effort, performed CPT tests and the recorded settlement case histories where consolidation settlements at the field under various surcharge loads were compiled from the Bursa East and West Waste Water Treatment Plant soil investigation projects. A database was composed of the results of 45 CPT and 57 settlement plate recordings. For the compilation of this database, a series of finite difference software FLAC-3D analyses were carried out to calculate the change in stress distribution under the settlement plates. A maximum likelihood framework was used for the development of compressibility behavior of soils. As a result of careful processing of available data, the cone tip resistance (qc), soil behavior type index (Ic) were selected as two important parameters effecting the value of the one-dimensional constraint modulus, M. The regression analysis which uses the settlement values recorded at the site and those computed using the change in the stress distribution, the thickness of the sublayers and the proposed one-dimensional constraint modulus were carried out to calculate the values of these model parameters. Two correlations based on the cone tip resistance and soil behavior type index were developed for the computation of the one-dimensional constraint modulus, M.
57

Estudo das vibrações induzidas por pedestres em passarelas de madeira / Study of pedestrian-induced vibrations on timber footbridges

Pedro Gutemberg de Alcântara Segundinho 17 May 2010 (has links)
No Brasil, o estudo a respeito das vibrações induzidas por pedestres em passarelas vem sendo realizado a partir do início dos anos 1990, para passarelas de concreto e de aço. No entanto, ainda não há registro de estudos desse tipo e a norma brasileira NBR 7190 (1997) de projeto de estruturas de madeira apresenta somente critérios de dimensionamento para carregamentos estáticos, no caso de passarelas de madeira. Nesse contexto, este trabalho tem como objetivo geral a análise teórica, numérica e experimental de passarelas de madeira simplesmente apoiadas, com vistas a propor recomendações de projeto relacionadas ao conforto humano nessas estruturas. Este estudo foi desenvolvido a partir da análise de diretrizes normativas e critérios sugeridos por diversos autores, da análise teórica de passarelas dimensionadas segundo os critérios da NBR 7190 (1997), de modelos numéricos construídos em elementos finitos e de ensaios experimentais em modelo reduzido. Entre as conclusões alcançadas, destaca-se que a formulação de Euler-Bernoulli é adequada para o cálculo da primeira frequência natural nas direções transversal vertical e transversal horizontal em passarelas de madeira simplesmente apoiadas; entretanto, especial atenção deve ser dada para a avaliação da rigidez à flexão na direção transversal horizontal. Finalmente, sugeriu-se uma proposta para verificação do estado limite de serviço devido às vibrações induzidas por pedestres em passarelas de madeira simplesmente apoiadas, no tocante ao cálculo de frequências e acelerações, a ser inserida na futura revisão da norma brasileira de projeto de estruturas de madeira. / In Brazil, studies about pedestrian-induced vibrations on footbridges have been carried out since the early 1990s, for concrete and steel footbridges. However, there is no record of such studies and the brazilian standard NBR 7190 (1997) for the design of timber structures only presents design requirements for static loads, in the case of timber footbridges. Therefore, this paper aims to general theoretical analysis, numerical and experimental simply-supported beams timber footbridges, with a view to proposing recommendations for projects related to human comfort in these structures. This study was developed from the study of standards guidelines and criteria suggested by several authors, the theoretical analysis of footbridges design according to the criteria of the NBR 7190 (1997), numerical models using finite element and experimental tests on reduced model. Among the conclusions reached, it is emphasized that the formulation of Euler-Bernoulli is suitable for calculating the first natural frequency in vertical and lateral directions simply-supported beams timber footbridges; however, special attention should be given to the evaluation of lateral bending stiffness. Finally, we have suggested a proposal serviceability limit state verification due to pedestrian-induced vibrations on simply-supported beams timber footbridges, concerning the calculation of frequencies and accelerations to be included in a future review of the brazilian standard for the design of timber structures.
58

Rekonstrukce zásobníku na slínek / Reconstruction of the cement component storage structure

Bažantová, Lenka January 2018 (has links)
The thesis is focused on the design of the reconstruction of the reinforced concrete pre-stressed construction of the clinker reservoir. The supporting system of the structure consists of a reinforced concrete wall on which a prestressing reinforcement is applied in the sprayed concrete layer. Preliminary research revealed disturbances that could disrupt static objects. The aim of this work is to propose a solution for the reinforcement of the supporting structure. The thesis contains two variants of the reconstruction solution. A static report is prepared for the selected option, including the impact of the construction, the construction procedure and the drawing documentation.
59

Návrh a kontrola parametrů zásobní smyčky linky pro zpracování plechu / Design and examination of parameters of the line stock loop for sheet metal processing

Novák, Tomáš January 2020 (has links)
Master thesis is focused on determination of stress and deformation state of metal sheet in stock loops of non-standard dimension. The main goal was creating numerical model and de-termination of maximal possible stock of metal sheet for all requested parameters. The problem was solved using Finite element methods in the software ANSYS. Results were handed to ŽĎAS, a.s. corporation, where they will be used for design of the lines for metal sheet proces-sing of non-standard dimension. Another goal was estimation, how the residual stress in metal sheet can effect the observed stress state.
60

Statické řešení založení novostavby horského hotelu / Static solution of new mountain hotel building foundations

Velecká, Renata January 2014 (has links)
Master's thesis deals with design and static solution of foundation slab of mountain hotel. Two calculation versions are made – simplified („inverse ceiling“) and calculation using software RF-SOILIN. This thesis also includes a comparison of both results. Reinforcement is designed for more accurate internal forces and the assessment of structure is performed according to the 1st limit state of capacity.

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