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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.
1

Infästningar för korslimmat trä : Tänkbara infästningar för ett 22-våningshus i KL-trä samt deras styvheters betydelse för de horisontella deformationerna

Elgerud, Freja, Sandström, Isabel January 2017 (has links)
Intresset för flervåningshus i trä ökar stadigt. Trä är ett lätt och mjukt material vilket är problematiskt med avseende på stomstabilisering och horisontella deformationer. Syftet har varit att undersöka förbandstyper för KL-trä och huvudfrågan var hur stommens horisontella deformationer påverkas av infästningstyperna och deras styvhet. En jämförande studie av självborrande skruvar och beräkning av deras förskjutningsmodul har utförts. En modell på 22 våningar med en stomme av KL-trä modellerades i RFEM. Analyser genomfördes för olika värden på förskjutningsmodul för att kunna jämföra de horisontella deformationerna. Resultatet visade på att deformationerna blev små och att skillnaden mellan olika förskjutningsmoduler gav en knappt märkbar skillnad i horisontell deformation, trots att variationen av värdet på förskjutningsmodulerna var stor. Detta kan förklaras av att modellen i sig är väldigt stabil, vilket främst skulle kunna bero på fasadelementens vertikala förskjutning och höjd. Andra bidragande orsaker var att modellen saknade urtag för dörrar och fönster, KL-elementens tjocklek samt att pågjutning av betong applicerades på varje våning. / The interest for multi storey buildings with timber is growing. Timber is a material that is light and ductile, characteristics that make timber a challenging material in terms of horizontal stabilization and horizontal displacements. The purpose was to examine connectors for CLT and the main question was how the horizontal displacement of the frame is affected by the connectors and their stiffness. A parametric study for self-tapping screws and calculation of their slip modulus was carried out. A model of a 22-storey building with a CLT frame was modelled in RFEM. Analyses were run for different values of the slip modulus for comparison of the horizontal displacements connected to each slip modulus. The results show that the deformations were small and that the differences in slip modulus only caused small differences in horizontal deformations even though the variation in slip modulus was wide. The reason for this could be due to the modelling; the model in itself is very stiff, possibly as a result of the façade panels’ vertical adjustment and height. Other factors contributing were the lack of openings for doors and windows in the model, the thickness of the CLT panels as well as the concrete decks on all floors.
2

Vypracování algoritmu a příslušného programového modulu pro statické a dynamické řešení lan na kladkách / Development of algorithm and pertinent program mogule for statical and dynamical analysis of cables on pulleys

Štekbauer, Hynek January 2015 (has links)
The goal of this master thesis is to develop an algorithm for solving cables on pulleys, which would be more efficient and accurate than existing algorithm used in software RFEM. This algorithm was integrated to the program for static and dynamic analysis of structures, in the form of particular program module. This work also contains examples of using this algorithm. The comparison of expected results with outcomes from the program is presented. The suitability for common practise is examined based on this comparison. The examples showed that the new algorithm for solving of cables on pulleys is more powerful and more accurate than existing solutions and most likely does not has equivalent competition.
3

Implicitní a explicitní metoda v nelineární dynamice / Implicit and Explicit Method in nonlinear Dynamics

Vaněčková, Adéla January 2017 (has links)
The final thesis „Explicit and Implicit methods in nonlinear dynamics“ deals with the issue of geometrical and physical nonlinear analysis of structures exposed to seismic loading by the methods of direct integration of equations of motion. Solution by the explicit and the implicit method is compared for three material models. While the differences between the results of the explicit method and the implicit Newmark method are small as expected, the differences are substantial between the results of different material models. However, these differences are explained and they are in full concordance with the theoretical assumptions for the pertinent material models. The conclusion of the final thesis is check of correctness of the results of the new module of the program system RFEM for both tested numerical methods and all three analyzed material models. (linear elastic, plastic Drucker-Prager and the Mazars damage model). With sufficient precision of results, both explicit and implicit numerical methods showed to be suitable for seismic analysis. The implicit method can provide several times faster calculation than the explicit one, but the determination of the optimal time step is problematic and time consuming, so the suitability of use of both methods for seismic analysis is comparable.
4

Dynamic Blast Load Analysis using RFEM : Software evaluation

Dädeby, Oskar January 2021 (has links)
The purpose of this Master thesis is to evaluate the RFEM software and determine if it could be used for dynamic analyses using blast loads from explosions. Determining the blast resistance for a structure is a growing market and would therefore be beneficial for Sweco Eskilstuna if RFEM could be used for this type of work. The verification involved comparing the RFEM software to a real experiment which consisted of a set of blast tested reinforced concrete beams. By using the structural properties from the experiment project with the experiment setup the same structure could be replicated in RFEM. RFEM would then simulate a dynamic analysis loaded with the same dynamic load measured from the experiment project in two different dynamic load cases caused by two differently loaded explosions. The structural response from the experiment could then be compared to the response simulated by the RFEM software, which consisted of displacement- and acceleration time diagrams. By analysing the displacement and acceleration of both the experiment and the RFEM software the accuracy was determined, and how well RFEM preformed the analysis for this specific situation. The comparison of the displacement and acceleration between the experiment and RFEM was considered acceptable if the maximum displacement was consistent with the experiments result and within the same time frame. The acceleration was considered acceptable if the initial acceleration was consistent with the experiment result. These criteria needed to be met for the verification that RFEM could simulate a dynamic analysis. If the software managed to complete a dynamic analysis for two dynamic load cases, then the software could be evaluated which consisted of determining if the post blast effects could be determined and if the modelling method was reliable.  The acceleration from RFEM were in good agreement with the experiment test at the initial part of the blast, reaching a close comparison for both load cases after 3 ms. Then the RFEM acceleration had a chaotic behaviour reaching no similarities for the duration of the blast. The displacement managed to get a close comparison of the maximum displacement with a margin of 0,5 mm for both load cases within a 1 ms time margin. RFEM managed in conclusion to simulate a blast load analysis, the displacement and acceleration gave acceptable results according to the criteria.  With the method chosen a fast simulation was achieved and with the same model complying with two different load cases for the same model gave indication that the first result was not a coincidence. The steps taken in the modelling method was straight forward, but two contributing parameters were determined to devalue the reliability. First parameter was the material model chosen for the concrete, which was chosen to a plastic material model. The two optional material model’s linear elastic and non-linear elastic both caused failed simulations. Also, the better model for the material model would have been a diagram model which insured that the concrete lost is capacity in tension with maximum capacity, but this was not available in a dynamic analysis with multiple load increments. Which is the reason why a plastic material model was chosen for the concrete. The second reason was the movement of the beam in the supports. This data was not recorded in the experiment but was determined to be a contributing part of the test. This however gave big differences of the result depending on how much the beam could move. In the end the best possible result was chosen to comply with the first load case where the same RFEM model was used in the second test. The second load case showed just as good results as the first load case, but with the big variation in results depending on the movement of the beam in the supports made this part unclear.  For the evaluation the question if the RFEM could provide a post blast analysis needed to be addressed, where the answer is no. The failure mode was chosen to comply with the choice of modelling method which required the analysis of the plastic strain in the reinforcement bars. This information was not available using the add-on module DYNAM-PRO and could therefore not provide the answer if the model structure resisted the blast.  For future work of this master thesis is to build a model that would give a more detailed post blast analysis, where this thesis was made to test the software. For this more work would be necessary by the creators Dlubal to further improve the add-on-module, which involves more extractable results and more detailed tools when using a dynamic load case, where some important functionality is only usable in a static load case. Other than that, RFEM managed to complete the dynamic analysis, and with further improving of the modelling method a more detailed analysis can be made and then be usable in real projects in the future.
5

Statické řešení monolitické konstrukce administrativní budovy / Static solution of a monolithic structure of an office building

Friedová, Lenka January 2022 (has links)
The master thesis is focused on the design and assessment of the monolithic structure of an office building, respectively their main parts - slab, span, columns and basement wall. The static solution is performed in the SCIA Engineer 20.0.2028 computer program. The output of the thesis is a static calculation and drawing part, which is processed in AutoCAD software.
6

Studie nárazu dopravního prostředku do stavební konstrukce. / Study of impact of a transport vehicle into a structure.

Sychrová, Šárka January 2013 (has links)
Master's thesis deals with the analysis of the impact of transport vehicle on a building structure. Transport vehicle is represented by an airliner and building structure is represented by a containment of a nuclear power plant. The aim of thesis was to explore the possibility of numerical simulation of an impact of transport vehicle on a building structure utilizing the RFEM program and evaluation of the damage extent.
7

Composite timber structures – Ribbed plate design : Evaluation of existing and development of new design methods

Mård, Cristoffer January 2022 (has links)
Ribbed plates comprising cross-laminated timber slab, CLT, with glulam beams allow for increased span length compared to pure CLT slabs. At the moment the Eurocodes do not provide any recommendations to design a CLT plate or a ribbed plate. There are handbooks for designing ribbed plates. But are their methods the best suited? Should one use Eurocode’s gamma-method, Timoshenko, shear analogy method or maybe an FE-model? This is difficult to answer, but nevertheless important questions for a structural engineer today. This master thesis investigates some of the different design methods used today in a numerical study. The study compares analytical methods and FE-models by investigating different parameters, like span lengths 6 m, 12 m, and 18 m, or uniform load and point load. Furthermore, this thesis provides guidance and help to apply design methods for ribbed plates. The outcome of the study shows a tendency for the gamma-method and the extended gamma-method giving the lowest deflections and normal stresses in many situations. Thus, there could be a risk of underestimating these properties by using the gamma-method. On the other hand there were consistent results with the gamma-methods compared to Timoshenko- and shear analogy-method which showed more deviations from the extended gamma-method as reference. The Timoshenko-method showed anomalies with thicker CLT. In addition, an Abaqus model with 3D elements and RFEM models with 2D and 1D elements were applied. The Abaqus models gave in general higher deflections and consistent results. Concluding from this thesis the Abaqus model together with the extended gamma-method would complement each other most efficiently in the design process of ribbed plates.
8

A pre-study of the static behaviour of a single diagonal timber arch bridge

Öhgren, Lovisa, Åström, Malin January 2020 (has links)
The aim of this thesis is to study and gain more insight about the static behaviour of the three hinged single diagonal timber arch bridge in different situations. The bridge was tested for static analyses for both Ultimate Limit State and Serviceability Limit State, to investigate its behaviour and if it is possible to be built at the selected location. Furthermore, the dimensions of the elements are to be determined. Pre-studies on similar bridges have been done and their problems have been taken into account when analysing the behaviour of this bridge. Thereafter, two different designs have been constructed. The finite element software RFEM has been used in this project to be able to analyse the behaviour of the two different models. The in-plane buckling of the arch is the most critical part of the bridge and the bridge should therefore be designed regarding that. Additionally, different alternatives were suggested to reduce the deformation of the deck in the models. Finally, an optimized model is reached which consists of longitudinal beams and has an arch with a wide cross section.
9

Klopení nosníku - analýza specifických případů / Lateral-torsional buckling of beams - analysis of specific cases

Piják, Jiří January 2017 (has links)
Thesis deals with flexural-lateral buckling of asymmetric cross sections, especially assessment according to ČSN EN 1993-1-1. Models are based on bar, shell and solid finite element method. Assessment of software Scia Engineer and RFEM are analysed in bar model. Plate and volume model uses shell and solid elements and initial imperfections. Computing is geometrically nonlinear. Correspondence of bar and plate model is studied. Optimal amplitude is suggested. Simple beam loaded with continuous line loading is taken as an example.
10

Statické řešení železobetonové konstrukce / Static solution of a reinforced concrete structure

Zedník, Tomáš Unknown Date (has links)
This diploma thesis deals with the design of a mountain hotel with a roof structure made of a reinforced concrete shell. During designing three types of design were assessed. The aim was to find out which of the design solutions is the most suitable for the behaviour of a reinforced concrete structure. The Dlubal RFEM program was used to assess and calculate the internal forces in the structure. In this thesis I also deal with the design and assessment of individual elements of the selected design solution. The thesis also includes drawings of construction plans and drawings of reinforcement plans.

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