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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.
31

Koncepční návrh letounu VUT 001 Marabu podle předpisu CS-22 / Marabu VUT 001 Aircraft Conceptual Design according to CS-22 Regulation

Navrátil, Jan January 2008 (has links)
Thesis summarizes conceptual design of VUT 001 Marabu airplane modification to fulfill CS-22 regulation requirements. Aerodynamical optimalization of wing and horizontal tail geometry is solved. Aerodynamical characteristics, performance and stability is analysed and basic structural design of wing and horizontal tail is performed.
32

Conceptual design of a material handling system for a county airport mail center

Napisa, Rodolfo R. 16 December 2009 (has links)
Master of Science
33

Synergetic Building Integrated Agriculture in the design of a multi-functional building

Lundgren, Tobias January 2021 (has links)
This thesis has as the main objective to investigate how to mitigatenegative impacts of urban environments and industrial agriculturethrough architectural design. The applied methodology is based inSynergetic Building Integrated Agriculture (SBIA) in combinationwith strict sustainability requirements (ecological, economical andsocial). Through the qualitative study of SBIA and built case studies it waspossible to identify the common factors and state-of-art technologyto be integrated in the design. This synergetic design proposal thus highlights the importance of amultidisciplinary approach for a successful future implementation ofsustainable SBIA design.
34

Incorporating Computational Fluid Dynamics Into The Preliminary Design Cycle

Shelley, Jonathan Knighton 27 July 2005 (has links) (PDF)
Industry is constantly looking for ways to bring new or derivative products to market in the shortest amount of time for the least amount of money. To accomplish this, Industry has adopted Computer Aided Engineering (CAX) tools that perform structural, flow, manufacturing, and cost analysis. The way in which a company utilizes these CAX tools can determine the success of these new products. One of these tools that Industry often struggles with in the preliminary design of a product is Computational Fluid Dynamics (CFD). Some of the challenges presented by CFD are the time it takes to create a CAD model, generate a valid grid for analysis, obtain a solution, post-process results, and review the result. The objective of this thesis is to develop an approach that will reduce the time it takes to go from a concept to a solution ready for review. This approach, addresses how to first, build CAD model for use in downstream applications, second, automate the grid generation process, and third, automate the post process and documentation of the results. Using this approach a conceptual study of a two stream mixing problem was performed. The approach showed that the creation of the first model took about twenty percent longer than the standard practice used in industry today. However, once the first model was completed, different concepts could be added to the CAD model and be ready for analysis in less than half the time when compared to standard practices. This time savings can then be used to explore more concepts. After each model was analyzed, it was post-processed using an automated script. With the post-processed results the Design Review Tool (DRT) was developed to automate the documentation of the results. Using the DRT each post-processed case was organized into a web page and saved for review in less than five seconds. This approach will enable the aerospace, automotive, and other industries to use CFD to more effectively explore the design space in the development of new and derivative products. This research demonstrates the process to reduce the time required to go from CAD-to-Grid, postprocess the results, and create the documentation needed to develop new products.
35

A Method for Exploring Optimization Formulation Space in Conceptual Design

Curtis, Shane Keawe 09 May 2012 (has links) (PDF)
Formulation space exploration is a new strategy for multiobjective optimization that facilitates both divergent searching and convergent optimization during the early stages of design. The formulation space is the union of all variable and design objective spaces identified by the designer as being valid and pragmatic problem formulations. By extending a computational search into the formulation space, the solution to an optimization problem is no longer predefined by any single problem formulation, as it is with traditional optimization methods. Instead, a designer is free to change, modify, and update design objectives, variables, and constraints and explore design alternatives without requiring a concrete understanding of the design problem a priori. To facilitate this process, a new vector/matrix-based definition for multiobjective optimization problems is introduced, which is dynamic in nature and easily modified. Additionally, a set of exploration metrics is developed to help guide designers while exploring the formulation space. Finally, several examples are presented to illustrate the use of this new, dynamic approach to multiobjective optimization.
36

The Investigation of an Inboard-Winglet Application to a Roadable Aircraft

Intaratep, Nanyaporn 20 June 2002 (has links)
The inboard-winglet concept was examined for its flow characteristics by testing for pressure coefficients over the wing and winglet surface in the Virginia Tech Stability Wind Tunnel over a range of freestream velocity and angle of attack. The results were analytically applied to calculate aircraft performance of a roadable aircraft, Pegasus II, which used the inboard-winglet concept in its design. The results proved that this concept has the potential to increase a wing lift coefficient at the right combination of thrust setting and freestream velocity better than a conventional wing-propeller arrangement. The lift coefficient inside the winglet channel was approximated as 2D in behavior. It is also shown that the winglets produce thrust at a positive-lift wing configuration. In the Pegasus II, the vertical stabilizers act like inboard winglets and produce a thrust component from its resultant force, giving 5.2% improvement in its effective aspect ratio and resulting in an induced-drag decrease. With an application of the new wing concept, the Pegasus II performance is comparable to other general aviation aircraft. / Master of Science
37

A Formal Consideration of User Tactics During Product Evaluation in Early-Stage Product Development

Owens, Trenton Brady 16 June 2022 (has links)
Frequent and effective design evaluation is foundational to the success of any product development effort. Products used, installed, or otherwise handled by humans would benefit from an evaluation of the product while formally considering both the physical embodiment of the technology, termed technology, and the steps a user should take to use that technology, termed tactics. Formal and simultaneous evaluations of both technology and tactics are not widespread in the product design literature. Although informal evaluation methods have advantages, formal methods are also known to be effective. In this paper we propose a formal method for evaluating tactics and technology simultaneously. Unlike the published literature, this evaluation involves explicitly defined tactics in the form of a written description of the actor, environment, and series of steps. It also involves the use of stage-appropriate, explicitly defined tactics-dependent criteria, which include criteria from a broad range of impact categories, such as impacts on the user, environment, project, and technology.
38

An expert system based advisor for the quality function deployment method

Chilakapati, Rajesh 29 July 2009 (has links)
A structured and disciplined Systems Engineering process is essential for the effective and efficient design and development of products and systems which are both responsive to customer needs and competitive in the global economy. The emphasis of this research is on the conceptual design phase of the Systems Engineering process. Conceptual system design is characterized by imprecision and vagueness. Designers make significant commitments to system-level design requirements and the system design concept in the face of this vagueness. Accordingly, the primary goal of this research is to develop an aid to facilitate the definition of system-level design requirements. During conceptual design, needs analysis and requirements definition is facilitated by the Quality Function Deployment (QFD) method. Quality Function Deployment is a design methodology chosen as the central focus of this research effort. Consistency within the QFD procedure must be maintained in order to accurately translate customer specified requirements into design requirements. This research, leading to the development of an expert system based advisor for system designers, is unique. A rule-based expert system was implemented to parse a completed QFD matrix and to identify occurrences of inconsistencies and strategic opportunities. / Master of Science
39

Decision-Making Support by a Value-Driven Design Model

Tao, Cheng January 2016 (has links)
This thesis analyses the use of value models as boundary objects to support decision making during conceptual design of Product-Service Systems. Compared to requirements-based models, value models are claimed to enhance understanding of the design problems and customer needs, as well as to help the design team in creating more value adding solutions. The work of this thesis was to prepare, conduct and analyse a series of design experiments, which are are based on the continuous observations of designers’ verbalized design considerations. Protocol analysis was conducted to investigate how value models perform as boundary objects in design, in comparison with requirements-based models. The time spent on each different activity in the protocol has been used as main proxy in the experiment. Data triangulation was ensured by the use of a questionnaire that was answered by all participants. Both methods revealed that in the preliminary phase, value models are more effective than requirements-based models in conveying intuitive value-related information, assessing intangibles value aspects, and encouraging discussions on value concerns.
40

Evaluation and automation of space habitat interior layouts

Simon, Matthew 27 May 2016 (has links)
Future human exploration missions beyond Earth vicinity will be demanding, requiring highly efficient, mass-constrained systems to reduce overall mission costs and complexity. Additionally, long duration transits in space and lack of Earth abort opportunities will increase the physiological and psychological needs of the crew, which will require larger, more capable systems to ensure astronaut well-being. As a result, the objective of habitat design for these missions is to minimize mass and vehicle size while providing adequate space for all necessary equipment and a functional layout for crew health and productivity. Unfortunately, a literature review of methods for evaluating the performance of habitat interior layout designs (including human-in-the-loop mockup tests, in-depth computer-aided design evaluations, and subjective design evaluation studies) found that they are not currently compatible with the conceptual phase of design or optimization because of the qualitative nature of the comparisons and the significant time required to generate and evaluate each layout. Failure to consider interior layout design during conceptual design can lead to increased mass, compromised functionality, and increased risk to crew; particularly for the mass, cost, and volume-constrained long duration human missions to cislunar space and Mars currently being planned by NASA. A comprehensive and timely quantitative method to measure the effectiveness of interior layouts and track the complex, conflicting habitat design objectives earlier in the design process is desired. A new, structured method and modeling framework to quickly measure the effectiveness of habitat interior designs is presented. This method allows for comparison of layouts at conceptual design and advances research in the previously unavailable capability to automate the generation of habitat interiors. This evaluation method features the development of a comprehensive list of quantifiable habitat layout evaluation criteria, the development of automatic methods to measure these criteria from a geometry model and designer inputs, and the application of systems engineering tools and numerical methods to construct a multi-objective value function measuring the overall habitat layout performance. In particular, this method featured the separation of subjective designer preferences and quantitative evaluation criteria measurements to speed layout evaluations and enable automation of interior layout design subject to a set of designer preferences. This method was implemented through the construction of a software tool utilizing geometry modeling coupled with collision detection techniques to identify favorable layouts subject to multiple constraints and objectives (e.g., minimize mass, maximize contiguous habitable volume, maximize task performance efficiency). Notional cis-lunar habitat layouts were evaluated to demonstrate the effectiveness of the method. Furthermore, stochastic optimization was applied to understand and address difficulties with automated layout design, particularly constraint implementation and convergence behavior. Findings from these investigations and implications for future research are discussed.

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