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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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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.
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Showing 1 to 6 of 6 (0.053 seconds)Spelling suggestions: "subject:"dcotors (helicopters) design"" "subject:"dcotors (helicopters) 1design""
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A design study of a scale model bearingless helicopter rotor system using composite materialsCohen, Gary, M January 1991 (has links)
A thesis submitted to the Faculty of Engineering, University of the
Witwatersrand, Johannesburg, in fulfillment of the requirements for the
degree of Master of Science in Engineering. / The use of advanced composite materials in helicopter rotor systems offers
opportunities for improvements in aerodynamic geometry, performance,
weight, damage tolerarice, maintenance and operating costs. Technical aspects
of the design and analysis and the-practical aspects of the manufacture of a
composite rotor system are discussed herein. The rotor system was compared
to an existing conventional teetering rotor system, in order to establish the
viability of the new composite rotor system,
This rotor system reduced the number of components by 55% and the manufacturing time by half, due to the simplicity of the design and lay up procedure, thus
making the system economically more viable. The mass was predicted to within
1% of that achieved in practice and gave a mass advantage of 50.5% over the
conventional rotor. Static tests identified the failure modes and stress concentration
points, while. the comparative hover tests showed the system to have
±20% less drag. [Abbreviated Abstract. Open document to view full version] / AC2017
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Aerodynamic shape optimization via control theory of helicopter rotor blades using a non-linear frequency domain approachTatossian, Charles A. January 2008 (has links)
This study presents a discrete adjoint-based aerodynamic optimization algorithm for helicopter rotor blades in hover and forward flight using a Non-Linear Frequency Domain approach. The goal is to introduce a Mach number variation into the Non-Linear Frequency Domain (NLFD) method and implement a novel approach to present a time-varying cost function through a multi-objective adjoint boundary condition. The research presents the complete formulation of the time dependent optimal design problem. The approach is firstly demonstrated for the redesign of a NACA 0007 and a NACA 23012 helicopter rotor blade section in forward flight. A three-dimensional inviscid Aerodynamic Shape Optimization (ASO) algorithm is then employed to validate and redesign the Caradonna and Tung experimental blade. The results in determining the optimum aerodynamic configurations require an objective function which minimizes the inviscid torque coefficient and maintains the desired thrust level at transonic conditions.
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Aerodynamic shape optimization via control theory of helicopter rotor blades using a non-linear frequency domain approachTatossian, Charles A. January 2008 (has links)
No description available.
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Software integration for automated stability analysis and design optimization of a bearingless rotor bladeGündüz, Mustafa Emre 06 April 2010 (has links)
The concept of applying several disciplines to the design and optimization processes may not be new, but it does not currently seem to be widely accepted in industry. The reason for this might be the lack of well-known tools for realizing a complete multidisciplinary design and analysis of a product. This study aims to propose a method that enables engineers in some design disciplines to perform a fairly detailed analysis and optimization of a design using commercially available software as well as codes developed at Georgia Tech. The ultimate goal is when the system is set up properly, the CAD model of the design, including all subsystems, will be automatically updated as soon as a new part or assembly is added to the design; or it will be updated when an analysis and/or an optimization is performed and the geometry needs to be modified. Such a design process takes dramatically less time to complete; therefore, it should reduce development time and costs. The optimization method is demonstrated on an existing helicopter rotor originally designed in the 1960's. The rotor is already an effective design with novel features. However, application of the optimization principles together with high-speed computing resulted in an even better design. The objective function to be minimized is related to the vibrations of the rotor system under gusty wind conditions. The design parameters are all continuous variables. Optimization is performed in a number of steps. First, the most crucial design variables of the objective function are identified. With these variables, Latin Hypercube Sampling method is used to probe the design space of several local minima and maxima. After analysis of numerous samples, an optimum configuration of the design that is more stable than that of the initial design is reached. The process requires several software tools: CATIA as the CAD tool, ANSYS as the FEA tool, VABS for obtaining the cross-sectional structural properties, and DYMORE for the frequency and dynamic analysis of the rotor. MATLAB codes are also employed to generate input files and read output files of DYMORE. All these tools are connected using ModelCenter.
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The role of mission requirements, vehicle attributes, technologies and uncertainty in rotorcraft system designBaker, Andrew Paul 05 1900 (has links)
No description available.
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A plm implementation for aerospace systems engineering-conceptual rotorcraft designHart, Peter Bartholomew 08 April 2009 (has links)
The thesis will discuss the Systems Engineering phase of an original Conceptual Design Engineering Methodology for Aerospace Engineering-Vehicle Synthesis. This iterative phase is shown to benefit from digitization of Integrated Product&Process Design (IPPD) activities, through the application of Product Lifecycle Management (PLM) technologies. Requirements analysis through the use of Quality Function Deployment (QFD) and 7 MaP tools is explored as an illustration. A "Requirements Data Manager" (RDM) is used to show the ability to reduce the time and cost to design for both new and legacy/derivative designs. Here the COTS tool Teamcenter Systems Engineering (TCSE) is used as the RDM. The utility of the new methodology is explored through consideration of a legacy RFP based vehicle design proposal and associated aerospace engineering. The 2001 American Helicopter Society (AHS) 18th Student Design Competition RFP is considered as a starting point for the Systems Engineering phase. A Conceptual Design Engineering activity was conducted in 2000/2001 by Graduate students (including the author) in Rotorcraft Engineering at the Daniel Guggenheim School of Aerospace Engineering at the Georgia Institute of Technology, Atlanta GA. This resulted in the "Kingfisher" vehicle design, an advanced search and rescue rotorcraft capable of performing the "Perfect Storm" mission, from the movie of the same name. The associated requirements, architectures, and work breakdown structure data sets for the Kingfisher are used to relate the capabilities of the proposed Integrated Digital Environment (IDE). The IDE is discussed as a repository for legacy knowledge capture, management, and design template creation. A primary thesis theme is to promote the automation of the up-front conceptual definition of complex systems, specifically aerospace vehicles, while anticipating downstream preliminary and full spectrum lifecycle design activities. The thesis forms a basis for additional discussions of PLM tool integration across the engineering, manufacturing, MRO and EOL lifecycle phases to support business management processes.
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