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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

A knowledge-based engineering tool for aiding in the conceptual design of composite yachts

Payne, Rozetta Mary, Mechanical & Manufacturing Engineering, Faculty of Engineering, UNSW January 2008 (has links)
Proposed in this thesis is a methodology to enable yacht designers to develop innovative structural concepts, even when the loads experienced by the yacht are highly uncertain, and has been implemented in sufficient detail to confirm the feasibility of this new approach. The new approach is required because today??s yachts are generally lighter, getting larger and going faster. The question arises as to how far the design envelope can be pushed with the highly uncertain loads experienced by the structure? What are the effects of this uncertainty and what trade-offs in the structural design will best meet the overall design objectives? The new approach provides yacht designers with a means of developing innovative structural solutions that accommodate high levels of uncertainty, but still focus on best meeting design objectives constrained by trade-offs in weight, safety and cost. The designer??s preferences have a large, and not always intuitive, influence on the necessary design trade-offs. This in turn invites research into ways to formally integrate decision algorithms into knowledge-based design systems. A lean and robust design system has been achieved by developing a set of tools which are blanketed by a fuzzy decision algorithm. The underlying tool set includes costing, material optimisation and safety analysis. Central to this is the innovative way in which the system allows non-discrete variables to be utilized along with new subjective measures of structural reliability based on load path algorithms and topological (shape) optimisation. The originality in this work is the development of a knowledge-based framework and methodology that uses a fuzzy decision making tool to navigate through a design space and address trade-offs between high level objectives when faced with limited design detail and uncertainty. In so doing, this work introduces the use of topological optimisation and load path theory to the structural design of yachts as a means of overcoming the historical focus of knowledge-based systems and to ensure that innovative solutions can still evolve. A sensitivity analysis is also presented which can quantify a design??s robustness in a system that focuses on a global approach to the measurement of objectives such as cost, weight and safety. Results from the application of this system show new and innovative structural solutions evolving that take into account the designers preferences regarding cost, weight and safety while accommodating uncertain parameters such as the loading experienced by the hull.
12

Modellering och robusthetsanalys med parametrisk design : Effektivare visualisering av alternativa lastvägar vid bortfall av pelare

Kayhan, Özge, Mohamed, Zahra January 2020 (has links)
Today, 3D modelling and structural analysis of buildings are performed in various software. Collaboration between various software is common today but breaks the flow in the construction design phase. To achieve an uninterrupted flow in the construction design phase, a constellation of modelling and structural analysis is needed in a single software. To enable a constellation, there are today many developed digital methods for this.Parametric design is a digital method that is mostly used to handle complex shapes. In recent years, the parametric design has evolved even more and the algorithmic thinking in parametric design provides opportunities for performing structural analyses. The development includes various plug-in programs that have structural analysis capabilities. However, this degree project emphasizes that this can be achieved without a plug-in program that has structural analysis capabilities. With only one visualization program and a plug-in that handles visual programming, the ability to produce what is to be visualized with a script arises.The structural analysis in this thesis includes robustness analysis that is important in the context of progressive collapse, and only the alternative load path method is considered. Progressive collapse is an important analysis for buildings that arise due to known or unknown accident loads. To increase the redundancy of the bearing structure, the alternative load path method can be used, which is a branch under unknown accident loads.Robustness analysis is a time-consuming process and automation can make this more efficient. With parameter-driven modelling and robustness analysis, the constructor can indicate at an early stage possible structure failure before the building is completed. Early action also leads to a reduction in waste of material resources.The alternative load path method provides the possibility to analyze whether the building receives alternate load path in the event of loss of load-bearing elements. This research report analyses column loss. Automated visualization of alternate load path enables to be able to analyze the load redistribution after the loss of column.Today some buildings are at risk against the progressive collapse, people's lives and health are therefore at risk when all or part of the building collapses. That is why efficiency is needed. The research report showed that the script automated the modelling and robustness analysis of buildings. Two different loss scenarios were analyzed and the authors found different updated loading areas and load redistribution.
13

Aerodynamic Load Characteristics Evaluation and Tri-Axial Performance Testing on Fiber Reinforced Polymer Connections and Metal Fasteners to Promote Hurricane Damage Mitigation

Canino-Vazquez, Iván R. 13 November 2009 (has links)
Damages during extreme wind events highlight the weaknesses of mechanical fasteners at the roof-to-wall connections in residential timber frame buildings. The allowable capacity of the metal fasteners is based on results of unidirectional component testing that do not simulate realistic tri-axial aerodynamic loading effects. The first objective of this research was to simulate hurricane effects and study hurricane-structure interaction at full-scale, facilitating better understanding of the combined impacts of wind, rain, and debris on inter-component connections at spatial and temporal scales. The second objective was to evaluate the performance of a non-intrusive roof-to-wall connection system using fiber reinforced polymer (FRP) materials and compare its load capacity to the capacity of an existing metal fastener under simulated aerodynamic loads. The Wall of Wind (WoW) testing performed using FRP connections on a one-story gable-roof timber structure instrumented with a variety of sensors, was used to create a database on aerodynamic and aero-hydrodynamic loading on roof-to-wall connections tested under several parameters: angles of attack, wind-turbulence content, internal pressure conditions, with and without effects of rain. Based on the aerodynamic loading results obtained from WoW tests, sets of three force components (tri-axial mean loads) were combined into a series of resultant mean forces, which were used to test the FRP and metal connections in the structures laboratory up to failure. A new component testing system and test protocol were developed for testing fasteners under simulated tri-axial loading as opposed to uni-axial loading. The tri-axial and uni-axial test results were compared for hurricane clips. Also, comparison was made between tri-axial load capacity of FRP and metal connections. The research findings demonstrate that the FRP connection is a viable option for use in timber roof-to-wall connection system. Findings also confirm that current testing methods of mechanical fasteners tend to overestimate the actual load capacities of a connector. Additionally, the research also contributes to the development a new testing protocol for fasteners using tri-axial simultaneous loads based on the aerodynamic database obtained from the WoW testing.
14

Integrale Planung und Herstellung von ressourceneffizienten Betonbauteilen aus mineralischer Faserverbundbewehrung und gradiertem Beton

Nigl, David, Schmeer, Daniel, Haase, Walter, Schönemann, Benjamin, Lenz, Katrin, Steier, Steffen, Sawodny, Oliver, Leistner, Philip, Blandini, Lucio, Sobek, Werner 21 July 2022 (has links)
Das Ziel des vorliegenden Projektes war es, eine sortenreine und gewichtsoptimierte Betonbauweise unter Einsatz mineralischer und lastpfadgerechter Faserverbundbewehrungen zur vorwettbewerblichen Anwendung weiterzuentwickeln, um damit neue Geschäftsfelder für KMU im Bereich des Bauwesens zu eröffnen sowie längerfristig den Technologiestandort Baden-Württemberg zu stärken. Dabei knüpft das Projekt nahtlos an die Arbeiten aus dem SPP 1542 – Leicht bauen mit Beton – an. Der vorliegende Kurzbericht fasst die Forschungsergebnisse zusammen. Für eine ausführlichere Beschreibung der Arbeiten sowie die Darstellung der Ausgangslage wird auf [1] sowie auf die Homepage [2] verwiesen. / The objective of the current project is to further develop a weight-optimised concrete construction method using mineral and load-path compatible fibre-composite reinforcements for pre-commercial applications. The outcome of the project could open new business opportunities for small- and mid-size enterprises in the construction sector and, in the longer term, strengthen Baden-Württemberg as a technology hub. The project seamlessly ties in with the previous work from SPP 1542, the results of which are summarised in this short report. For a more detailed description of the work readers are referred to [1] as well as to the homepage [2].

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