Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 35 for “"Variable Geometry"”.
-
Mobility analysis of variable geometry trusses
… in terms of increased strength and rigidity. Variable geometry trusses (VGTs) are a special class of parallel trusses. Literature on VGTs has covered many interesting problems, yet there has been no conscious effort to formulate a definition for a VGT. The major emphasis of this thesis is …
-
Grid Generation and CFD Analysis of Variable Geometry Screw Machines
… and numerical methods for predicting the flow in variable geometry, positive displacement screw machines. It has been shown, from a review of available literature, that the two main approaches available to generate deforming grids for the CFD analysis of 3D transient flow in screw machines are …
-
Kinematic analysis and animation of a variable geometry truss robot
… a parallel, closed-loop manipulator known as the Variable Geometry Truss or VGT for short. Widely recognized as adaptive or collapsing structures for space and military applications, VGTs have not received due consideration as robotic manipulators. VGTs undoubtedly represent an important sector of …
-
Design and construction of a double-octahedral variable geometry truss manipulator
… deals with the design and construction of a variable geometry truss (VGT) of the double-octahedral (pyramid-pyramid) geometry. The truss is expected to be the focus of several experimental research projects. In this thesis, a kinematic model is formulated, and the forward and inverse …
-
Variable Geometry Scramjet Combustor Cavity Multi-Dimensional Treatise for Performance Analysis
… Scramjet engines, the results showed that the variable geometry matched or outperformed the baseline HiFiRE geometry. The analysis revealed points of Mach and altitude where certain combustor volumes demonstrated greater performance. This greater performance is only gained by the ability to …
-
Shape control of high degree-of-freedom Variable Geometry Truss manipulators
Variable Geometry Trusses (VGT’s) can be used as the fundamental building blocks in constructing long-chain, high degree-of-freedom manipulators. This thesis focuses on the kinematics of two such manipulators. It also illustrates how the concept of shape control can be applied to simplify the …
-
Design of a robotic manipulator using variable geometry trusses as joints
… workspace restrictions. The introduction of Variable Geometry Trusses (VGT’s) represents an opportunity to overcome this limitation. The lack of stiffness in many serial manipulators is primarily due to compliance at the joints. The disadvantage of the series connected device include …
-
The solution of variable-geometry truss problems using new homotopy continuation methods
A VGT or Variable-Geometry Truss can be thought of as a statically determinate truss that has been modified to contain some number of variable length members. These extensible members allow the truss to vary its configuration in a controlled manner. VGTs are often symmetric. constructed of …
-
Aerodynamic Analysis of Variable Geometry Raked Wingtips for Mid-Range Transonic Transport Aircraft
… designs for its next generation of airliners, a variable geometry raked wingtip novel control effector (VGRWT/NCE) was studied to determine the aerodynamic performance benefits over an untreated wingtip. The Boeing SUGAR design employing a truss-braced wing was selected as the baseline. Vortex …
-
Computational Analysis of Transient Unstart/Restart Characteristics in a Variable Geometry, High-Speed Inlet
… characteristics of a high-speed inlet with a variable-geometry, rotating cowl. The inlet analyzed is a mixed compression inlet with a compression ramp, sidewalls and a rotating cowl. The analysis is conducted at nominally Mach 4.0 wind tunnel conditions. Advanced Computational Fluid Dynamics …
-
A Comparative Study of the Low Speed Performance of Two Fixed Planforms versus a Variable Geometry Planform for a Supersonic Business Jet
… the same high speed performance as the baseline variable geometry wing. Following a review of high lift devices a detailed analysis of their use was conducted with the aid of vortex lattice method and empirical formulations. The slat and Fowler flap combination proved to be the best mechanical …
-
Inlet drag prediction for aircraft conceptual design
… Originally, the drag of only one inlet type, the variable-geometry conical inlet, could be calculated within ACSYNT. This prompted the present research which resulted in the creation of a modular suite of subroutines that extend the capability of ACSYNT. Using this new source code, ACSYNT can now …
-
Development of a 6 degree-of-freedom manipulator arm for use on an urban search and rescue robot
… survivors. The base is therefore equipped with variable geometry tracks to enable it to traverse stairs and other tricky terrain. The sensor payload is equipped with life detection equipment and the manipulator arm enables the USRR to manipulate with its environment (opening doors etc.) and to …
-
Tools for Analysis of Complex Geometries for a Combined Cycle SCRAM Jet / Rocket
<p>A preliminary design for a variable geometry combined cycle supersonic combustion ram jet (SCRAM jet) / rocket was developed. A precise geometry was selected by parametric analysis and the resultant geometry was analyzed using a computational fluid dynamics (CFD) code developed by Dr. Eric …
-
Development and performance of a miniature, low cost mass spectrometer
… consumption without sacrificing resolution. Variable geometry mechanical filters allow for variable resolution. An onboard ion pump removes the need for an external pumping source. An onboard digital controller allows a large degree of flexibility over the operation of the mass spectrometer …
-
A study of isostatic framework with application to manipulator design
… presents an original method to determine the geometry of general frameworks and an improved method to find the forces in their members. The determination of geometry and forces are critical areas in structural design. The second part of this dissertation presents a case study on one of the …
-
Open skies for Africa, a principled approach to the implementation of the Single African Air Transport Market (SAATM)
… the YD is to be undergirded by the principle of variable geometry, which is a concept in regional integration that allows countries to be flexible and pursue progressive and differentiated speed towards integration, by allowing a sub-group of countries that are willing and ready to advance to …
-
Kinematic Analysis of Tensegrity Structures
… (cables). Tensegrity structures can be used as variable geometry truss (VGT) mechanisms by actuating links to change their length. This paper will present a new method of position finding for tensegrity structures that can be used for actuation as VGT mechanisms. Tensegrity structures are …
-
Application of a design optimization strategy to multi-stage compressor matching
… in turbofan low-pressure compressors, where a variable geometry cannot be implemented, design strategies for maximum efficiency at high speed can compromise the surge margin at low speed. In this thesis, a design optimization framework has been implemented to an industry-strength …
Page 1 of 2