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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.
11

Ultimate load limit analysis of steel structures accounting for nonlinear behaviour of connections / Analyse limite ultime des structures en acier en prenant en compte le comportement non linéaire des connexions

Imamovic, Ismar 22 September 2017 (has links)
Cette thèse traite de l'analyse limite des structures de châssis en acier, qui s'utilise souvent comme la structure principale de support des bâtiments. La structure du cadre en acier est caractérisée par une réponse très ductile et un grand potentiel pour dissiper l'énergie, ce qui est crucial pour la résistance par rapport aux tremblements de terre. La ductilité dans la réponse de la structure est la cause du comportement du matériau lui-même et du comportement des connexions entre les éléments de la structure. Les connexions entre les poutres et les poteaux peuvent influencer de manière significative la réponse de la structure du cadre en acier, parfois jusqu'à 30%. L'idée est de intégrer le comportement des connexions par les éléments de poutres qui seront situés dans les coins du cadre et la modélisation du reste serra fait avec des éléments de poutres non-linéaires qui décrirons le comportement des poutres en acier. Cette recherche est composée de deux parties. La première partie est consacrée au comportement des connexions structurelles, la deuxième partie présente le développement de l'élément fini du faisceau non linéaire capable de représenter le comportement ductile d'un élément de la structure en acier. Dans la première partie de la thèse, nous définissons la procédure d'identification des paramètres constitutifs pour le modèle couplé de plasticité-dégâts avec dix-huit inconnus. Ce modèle constitutif est très robuste et capable de représenter une large gamme de problèmes. La procédure définie a été utilisée dans la préparation de tests expérimentaux pour trois types de connexions en acier structuré. Les tests expérimentaux ont été effectués pour deux cas de charge. Pour la première, la charge a été appliquée dans un sens avec les cycles de chargement et de déchargement. À partir des mesures expérimentales, nous avons conclu que le modèle de plasticité peut bien représentée le comportement de la connexion structurale. Paramètres constitutifs ont été déterminés à partir des résultats de l'expérimentation, on a utilisé une poutre géométriquement exacte avec la loi bilinéaires renforcement du matériel et la loi linéaire pour le ramollissement. Également, on a effectué des essais expérimentaux de deux types de raccords en acier en cas de chargement cyclique. Les données mesurées montrent que le modèle de la plasticité n'est pas assez bon pour décrire le comportement de connexion pour ce type de charge. A savoir, en raison de changements du sens de l'application du chargement, les connexions montrent moins de rigidité, qui peut être décrite avec un modèle constitutif de dommages. Pour cette raison, nous avons développé un nouveau modèle plasticité-dommages qui est capable d'inclure le phénomène mentionné ci-dessus. A la fin de cette section est faite l'identification des paramètres constitutifs. La deuxième partie de la thèse de doctorat est composé de formulations théoriques et la mise en œuvre numérique des faisceaux géométriquement exacte. La réponse de durcissement de la poutre comprend l'interaction entre les forces de la section résultant du stress (N, T et M), et la réponse de ramollissement est définit par la loi non linéaire. Ce type d'élément fini de poutre est capable de décrire le comportement ductile des structures en acier et inclure les effets du second ordre, qui sont très importantes pour l'analyse ultime des structures de cadre en acier. L'élément fini développé de poutre géométriquement exacte et les lois définies de liaison de comportement dans la construction en acier, offrant la possibilité d'une analyse de haute qualité des structures en acier. En utilisant les modèles de poutre proposé et la méthodologie de modélisation des structures de châssis en acier, il est possible de déterminer une distribution réaliste des forces de section transversale , y compris la redistribution due à la formation de rotules plastiques. / This thesis deals with the ultimate load limit analysis of steel frame structures. The steel frame structure has a very ductile response and a large potential to dissipate energy, which is crucial in the case of earthquakes. The ductility in the response of the structure comes from the behavior of the material itself and the behavior of the semi-rigid structural connections. The semi-rigid connections between beams and columns can significantly influence the response of the structure, sometimes up to 30%. In this thesis, we propose a methodology for modeling steel frame structures with included connection behavior. The idea is to model the behavior of the structural connections by the beam elements positioned in the corners of the steel frame structure. Other members of the steel frame structure, steel beams, and columns, will be modeled with nonlinear beam elements. This research consists of two parts. The first part deals with the behavior of the structural steel connections. In the second part, we present the development of the nonlinear beam element capable of representing the ductile behavior of steel structural elements, beams and columns. In the first part of the thesis, we define constitutive parameters identification procedure for the coupled plasticity-damage model with eighteen unknowns. This constitutive model is very robust and capable of representing a wide range of problems. The identification procedure was used in the preparation of experimental tests for three different types of structural steel connections. The experimental tests have been performed for two load cases. In the first, the load was applied in one direction with both the loading and unloading cycles. From the experimental measurements, we have concluded that the response of the experimental structure can be represented by the plasticity model only because no significant change in the elastic response throughout the loading program was observed. Therefore, we have chosen an elastoplastic geometrically exact beam to describe connection behavior. The hardening response of the beam is governed by bilinear law, and the softening response is governed by nonlinear exponential law. The identification of the parameters has been successfully done with fifteen unknown parameters identified. The two types of the experimental structures were also exposed to the cyclic loading. Measured experimental data shows complex connection behavior that cannot be described by the plasticity model alone. Namely, after changing load direction stiffness of the connection decreases. This suggests that the damage model should be incorporated in the constitutive law for the connections behavior as well. Therefore, we propose a new coupled plasticity-damage model capable of representing the loss in the stiffness of the connection with the changing of the load direction. At the end of this part, we also give the constitutive parameters identification for the proposed model. The second part of the thesis deals with the theoretical formulation and numerical implementation of the elastoplastic geometrically exact beam. The hardening response of the beam includes interaction between stress resultant section forces (N, T and M), and the softening response of the beam, which is governed by the nonlinear law. This type of the beam element is capable of representing the ductile behavior of a steel frame structure, and it takes into account second order theory effects. Performed numerical simulations show that the proposed geometrically nonlinear beam element is very robust and is able to provide a more precise limit load analysis of steel frame structures. By using proposed methodology for modeling steel structures, we are able to obtain the real distribution of section forces, including their redistribution caused by forming of the hinges and the connections behavior.
12

Víceůčelové obchodní centrum ve Vsetíně / The multipurpose shopping centre in Vsetín

Mužná, Alena January 2013 (has links)
Objective of the work is desingning the steel structure of multipurpose shopping centre. Structure is in two sections, structure A has two floors and structure B is ground floor. The main bearing components are the traversal restrained columns and the strut-frame stringers and traverse frames. Frame stringers are after the the axial distance 15 m. Ceiling are designed as a composite. The purlins are plate and trusses. The structure is desingned for the distrikt of east Morava.
13

Parkovací dům / Parking house

Frank, Ivo January 2016 (has links)
The subject of this thesis is to design the main supporting structure of the parking house in the city of Olomouc. The object has 7 storeys and rectangural dimensions are 57,2m x 37,0m. The height of the structure is 19,2m. The hall is designed by cylindrical roof. Processed design option is a composite steel-concrete floor slab.
14

Kaskádový dům / Tiered house

Dostál, Lukáš January 2017 (has links)
Project of a tiered apartment building. It is a four-storey above ground object.On the ground floor there are garages, storages and technical equipment of the building. The second to fourth storey are designated for dwelling, there are twelve housing units 1+1, three-bedroom flats with kitchenette and four-bedroom flats witch kitchenette. Some of the flats have cascade terraces. The load-bearing structure is made of cast-in-place concrete frame filled with concrete and clay masonry. The frame is founded on two-phased reinforced foundation blocks. The building is roofed with a main flat roof and walkable flat terraces adjacent to the flats. The building is thermally insulated with contact thermal insulation system.
15

Development of seamless woven node element structures for application in integral constructions

Fazeli, Monireh, Hübner, Matthias, Lehmann, Theo, Gebhardt, Ulrike, Hoffmann, Gerald, Cherif, Chokri 25 September 2019 (has links)
In order to advance consistent lightweight construction principles in automotive and mechanical engineering, support frame construction made from high-performance materials is becoming more commonplace. These consist of complexly structured nodular connection elements. The required connection elements have not yet been produced satisfactorily. The developed node element structures in this paper are produced on a shuttle weaving loom by flattening and weaving them as multi-surface woven fabrics. The development of the woven concept for the realization of node element structures is based on the fragmentation of the individual sub-elements. The goal of this research is development of a flexible technology for weaving fabrics and intended for the integral realization of woven nodular semi-finished products with complex geometries and connections, which are to be used to connect Fiber-reinforced Plastic components in support frame structures.
16

Centrum pro sport a volný čas Brno / Sports and Leisure Centre Brno

Vacenovská, Veronika January 2017 (has links)
The subject of the diploma thesis is an architectural study of the center for sport and leisure time in Brno “Za Lužánkami”. In is supposed to supply the space with the possibility of other sports activities. The object of the design is to provide a wide range of sports, fitness activities, wellness and recreation, various leisure activities, or just visiting the shopping passage, which is the main artery of the whole center. It allows people to pass between the leisure center, indoor pool and shopping mall in Královo Pole. The building is designed as a prefabricated reinforced concrete frame structure complemented by a steel latticework in the space of a sports hall and a climbing wall. Curtain walling is designed as a ventilated concrete slab with a photocatalytic function.
17

Statické řešení železobetonové konstrukce / Static solution of reinforced concrete structure

Mašek, Petr January 2018 (has links)
This diploma thesis deals with study of feasibility of waterpark monolithic reinforced concrete structure with roof terrace. This structure has one underground floor, which has water park utility function and two above ground floors. On the roof is terrace with grass, mobile bar and with space to relax. Subject of this diploma thesis is the main loadbearing frame, which has span 32 m. The structure is assessed according to limit states of valid norms and also takes into account construction stages and time dependent analysis. The structure is calculated on beam and slab-plate structural models. Structural analysis and general drawings are done.
18

Development of spatially branched woven node structures on the conventional weaving loom

Fazeli, Monireh, Hübner, Matthias, Lehmann, Theo, Gebhardt, Ulrike, Hoffmann, Gerald, Cherif, Chokri 05 November 2019 (has links)
The increasing need of consistent implementation of lightweight constructions in many technical fields makes the manufacture of near net-shaped node structure to be used in textile-reinforced composites a subject of great interest. The manufacture of the node structure is required to provide a strong node point whilst maintaining the circumference of each adjoining strut. Despite a variety of available methods to produce three-dimensional nodal fabric, the required geometry for the complex nodular connection element has not yet been fully achieved. Furthermore, the available methods have limitations. The developed woven concept in this work allows for maintaining the configuration of the node structure and dimensions of the tubes, especially at the node points. As a result, all tubes positioned at node points are fully open; this is accomplished without distorting the surrounding area once the flat woven node structure is removed from the loom and erected into three-dimensional configuration. In order to produce a three-dimensional structure on a conventional weaving machine, the structure must be flattened in an appropriate way. By using a mathematical algorithm, it is possible to graph the flattened structure precisely. The developed weaving concept and relating calculation are applied to create the weaving plan of the spatial nodal structures, which can be produced on a shuttle weaving loom. The developed concept in this paper will provide repeatable manufacturing of complex node structures by using the conventional weaving loom. The struts of node structures manufactured using this method can be woven at any angle and with spatial arrangements.
19

Řešení stability prutových konstrukcí / Stability solution of framed structures

Baxant, Radek January 2015 (has links)
This diploma thesis deals with the subject of slenderness bars’ stability assessment, especially in the steel structures. Before the assessment of bars in the frame constructions, we search for the influence of the computational model’s settings on the final result. The initial geometrical imperfections are examined on the model of Euler’s bar. The influence of the rigidity of girders on the poles’ buckling length is examined on the basic frame construction. The buckling lengths are assessed in the comparison with the figures we got from the statistical tables and the computational software. The influence of construction’s initial tilt and its replacement by the system of outer forces is examined on the frame structure. Three-hinged frame structure with variable cross-section member is designed then and the influence of non-linear calculations on the inner forces is studied. In the complex frame assessment, the influence of the number of parts of variable cross-section member on the bars’ buckling length is examined.
20

Statické posouzení stávajícího železobetonového skeletu výrobního objektu / Structural assessment of the existing reinforced-concrete frame structure of the production building

Pražan, Jiří January 2019 (has links)
The diploma thesis deals with the structural assessment of the existing reinforced concrete frame structure of the production building. The structure under consideration is carried out as a reinforced concrete monolithic frame structure with a discrepancy of 6,15 x 6,15 m (axis). The object has a rectangular plan of 13 x 9 fields. The total dimension is 56 x 81m and is divided into three dilation units on all floors by two inserted 3,65 m wide fields. The building has three above-ground floors and one underground floor. The construction height of the basement is 3,675 m, above ground level 4,0 m. On the west side of the building (axis A) are three reinforced concrete elevator shafts with a dimension of approximately 4,5 x 3,8 m. The envelope and inner partitions are made of bricks full of burned. The work shall include a static assessment of the status quo, a determination of the load capacity and a proposal for appropriate adjustments to ensure static reliability.

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