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- Dahlblom, Ola, et al.
(författare)
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Strukturmekanik - Modellering och analys av ramar och fackverk
- 2015
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Strukturmekanik är den del av fysiken som beskriver hur olika material, som formats och sammanfogats till strukturer, bär sina laster. Kunskapen om dessa strukturers verkningssätt kan användas i en skapande process där hållbara och effektiva, funktionella och uttrycksfulla byggnadsverk utformas. Den här läroboken i strukturmekanik baseras på finita elementmetodens metodik. Förståelsen för strukturmekaniska grundelement, fjädrar, stänger, balkar och fundament, byggs successivt upp i en, två och tre dimensioner. Med hjälp av dessa element visas hur komplexa bärande konstruktioner kan modelleras och analyseras. Metoder för såväl linjär som geometriskt och materiellt ickelinjär analys presenteras. För att synliggöra den beskrivna metodikens generalitet finns ett kort avsnitt som tar upp andra områden inom tillämpad mekanik som värmeledning och elektrisk strömning. Läroboken stödjer tre centrala lärandemål: • Kunskap i grundläggande strukturmekanisk teori. • Färdighet i att modellera och analysera strukturer. • Förmåga att i en designprocess värdera och effektivisera föreslagna konstruktionsutformningar. Läroboken vänder sig till civilingenjörsstudenter på kandidatnivå och till högskoleingenjörsstudenter. Datorprogram som stödjer bokens framställning finns att fritt ladda ner från hemsidan www.studentlitteratur.se/strukturmekanik. Andra upplagan
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| 2. |
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| 3. |
- Mohamed, Wael, et al.
(författare)
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A new and reusable foundation solution for onshore wind turbines
- 2017
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Ingår i: World Congress on Civil, Structural, and Environmental Engineering. - : Avestia Publishing. - 2371-5294.
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Konferensbidrag (refereegranskat)abstract
- Modern wind turbines are designed to withstand approximately for a lifetime of 20 years [1]. However, a very long design life of 100 years or more can be expected for high-quality concrete foundations. Thus there is a big difference in lifetime between wind turbines and foundations. There is a significant economic benefit of replacing the out-of-date wind turbine with a new turbine of better power generation capacity and reuse the existing foundation. However, the blades in modern turbines evolve to be longer, lighter and more efficient due to the rapid evolution of blade design which means a significant change in the design loads on the foundations. The big difference in lifetime and the major shift in the design loads show a potential for new and reusable foundation solution to allow wind power sites to be updated with taller and larger units in order to increase the energy production. A new foundation solution using a raft with an active stabilisation system is proposed in this study. The concept of an active stabilisation system is a novel idea using a movable load to stabilise against the overturning moment. The active stabilisation system consists of a water tank. The water tank is divided into eight compartments, and the system uses water as a movable load. Water will be in a number of compartments to stabilise against the overturning moment. Water position will rely on the wind direction. The water movement system depends on some electric motors and pipes with electric valves. The geotechnical performance of the new foundation solution is investigated in two studies using two existing weak soil profiles in Egypt and Sweden [2, 3]. The main result of these studies was that using a raft with an active system decreases the tilting compared to a piled raft with long friction piles. Moreover, it was found that the foundation budget is decreased in the case of using a raft with an active system compared to a piled raft with long friction piles.One of the advantages of the new foundation solution is that the stability moment can be increased by filling more compartments with water. The present study focuses on comparing the allowable load capacity of the mentioned foundation solution and a raft foundation according to bearing capacity considering four soil profiles. The results show that the stability moment using the new solution can be increased by almost 41%. Also, the results show that the new foundation system gives a substantial improvement of the foundation load capacity compared to the traditional foundation solution. The improvement of the load capacity in the case of weak soils is increased by 48% ~ 67% compared to a traditional raft foundation. The improvement of the load capacity in the case of strong soils is increased by 23% ~ 32% compared to a traditional raft foundation.
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| 4. |
- Mohamed, Wael, et al.
(författare)
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A new and reusable foundation solution for onshore windmills
- 2018
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Ingår i: Computers and Geotechnics. - : Elsevier BV. - 0266-352X. ; 99, s. 14-30
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Tidskriftsartikel (refereegranskat)abstract
- A new foundation solution using a cellular raft with an active stabilisation system is proposed in this work. A comparative study of the new foundation and a traditional raft is performed. This study focuses on comparing the load capacity of the mentioned foundation solutions. The results illustrate that a cellular raft with an active stabilisation system gives a substantial enhancement of the load capacity compared to a traditional circular raft. Also, reusing the new foundation solution will provide a significant reduction of the carbon dioxide emissions comparing to the complete dismantling of the existing foundation and building a new one.
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| 5. |
- Olsson, Karl-Gunnar, 1955, et al.
(författare)
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Structural Mechanics: Modelling and Analysis of Frames and Trusses
- 2016
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Textbook covers the fundamental theory of structural mechanics and the modelling and analysis of frame and truss structures: Deals with modelling and analysis of trusses and frames using a systematic matrix formulated displacement method with the language and flexibility of the finite element method. Element matrices are established from analytical solutions to the differential equations. Provides a strong toolbox with elements and algorithms for computational modelling and numerical exploration of truss and frame structures. Discusses the concept of stiffness as a qualitative tool to explain structural behaviour. Includes numerous exercises, for some of which the computer software CALFEM is used. In order to support the learning process CALFEM gives the user full overview of the matrices and algorithms used in a finite element analysis
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| 6. |
- Spetz, Alex, et al.
(författare)
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Isogeometric Analysis of Soil Plasticity
- 2017
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Ingår i: Geomaterials. - : Scientific Research Publishing, Inc.. - 2161-7546 .- 2161-7538. ; 7:3, s. 96-116
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we present numerical simulations of soil plasticity using isogeometric analysis comparing the results to the solutions from conventional finite element method. Isogeometric analysis is a numerical method that uses nonuniform rational B-splines (NURBS) as basis functions instead of the Lagrangian polynomials often used in the finite element method. These functions have a higher-order of continuity, making it possible to represent complex geometries exactly. After a brief outline of the theory behind the isogeometric concept, we give a presentation of the constitutive equations, used to simulate the soil behavior in this work. The paper concludes with numerical examples in two- and three-dimensions, which assess the accuracy of isogeometric analysis for simulations of soil behavior. The numerical examples presented show, that for drained soils, the results from isogeometric analysis are overall in good agreement with the conventional finite element method in two- and three-dimensions. Thus isogeometric analysis is a good alternative to conventional finite element analysis for simulations of soil behavior.
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