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 21 for “"Conceptual Aircraft Design"”.
-
Uncertainty budgeting methods for conceptual aircraft design
… management of uncertainty are critical in the design of engineering systems, especially in the early stages of conceptual design. This thesis presents an approach to defining budgets on the acceptable levels of uncertainty in design quantities of interest, such as the allowable risk in not …
-
Afterbody drag prediction for conceptual aircraft design
With the increasing performance demands placed on aircraft, the nozzle is becoming a much more versatile component. This versatility is increasing the afterbody complexity and the difficulty in afterbody drag prediction. This thesis documents a computationally inexpensive method for estimating the …
-
An Analysis of Using CFD in Conceptual Aircraft Design
… (CFD) package may be incorporated into a conceptual design method is performed. The repeatability of the CFD solution as well as the accuracy of the calculated aerodynamic coefficients and pressure distributions was also evaluated on two different wing-body models. The overall run times of …
-
Conceptual aircraft design for environmental impact : modeling operations for emissions assessment
… performance and economics. The Environmental Design Space (EDS) project explores the tradeoffs between noise, emissions, and economics for conceptual design of future aircraft. A key component to EDS is modeling the emissions of aircraft in operation. Traditional design tools need more …
-
Rule-based fuselage and spine and cross-section methods for computer aided design of aircraft components
In recent years, the use of computer-aided design (CAD) systems for conceptual aircraft design has greatly increased. As a result, new and better methods for creating surface models of aircraft geometry using dimensional parameters are needed. One such method, the Rule-Based Fuselage method, was …
-
Development of a CAD system for automated conceptual design of supersonic aitcraft
Development of a conceptual aircraft design system based on ACSYNT, an aircraft synthesis program written by the NASA Ames Research Center; is discussed. The system, named ACSYNT/VPI, was written using the PHIGS graphics standard for machine independence and designed based on top·down principles …
-
Reverse parameterization of B-spline surfaces for data transfer
… transferring B-spline surface data from a final design CAD tool to a parameter based conceptual design CAD tool. Both codes store data in different ways, requiring a technique referred to as reverse parameteriation to achieve data transfer. Methods are discussed to produce surface points from …
-
Transonic flutter prediction and aeroelastic tailoring for next-generation transport aircraft
Novel commercial transport aircraft concepts feature large wing spans to increase their fuel efficiency; these wings are more flexible, leading to more potential aeroelastic problems. Furthermore, these aircraft fly in the transonic flow regime, where utter prediction is difficult. The goals for …
-
Skinning engineering models with non-uniform, hierarchical B-spline surfaces
… hierarchical B-splines offer the mechanical designer many advantages: parametrically defined components may be added to a surface while maintaining C² surface continuity; detailed features may be added to a surface without globally affecting the B-spline control net; and an appropriate …
-
Intersection and filleting of non-uniform B-spline surfaces
Preliminary aircraft design codes requIre a more complete and integrated geometry definition than that used by conceptual design codes. This thesis documents the design and creation of an interactive CAD system which converts the geometry descriptions commonly used in conceptual aircraft design …
-
AeroSandbox: A Differentiable Framework for Aircraft Design Optimization
… work presents a new computational framework for conceptual aircraft design called AeroSandbox. This framework leverages modern techniques for automatic differentiation developed in the optimal control and machine learning communities. By combining these efficient gradient calculations with robust …
-
Development of an object-oriented graphical user interface for an aircraft engine cycle analysis program
… the recent introduction of the object-oriented design approach has proved successful. At the same time graphical user interfaces are gaining in popularity to improve the usability and versatility of an application. This thesis investigates the application of the object-oriented approach to the …
-
Structural analysis and optimization with a locally-Cartesian Hybrid Shell Model
… structural model well suited for conceptual design of aerospace vehicles. Although significantly simpler and more economical than full 3D elasticity models, it can still capture full 3D geometries, large deformations, and anisotropic materials. HSM is formulated from the full 3D …
-
Combat aircraft scenario tradeoff models for conceptual design evaluation
… knowledge to the field of combat aircraft survivability, and to create scenario-specific models in order to estimate the tradeoff between aircraft survivability and lethality metrics at the encounter and sortie levels. The development of scenario-specific models serves to identify …
-
Projection, design, and representation of curves on B-spline surfaces
In an interactive design process, tools that provide visual feedback on the design model are highly valuable. This research explores a specific topic of graphical visualization and geometric modeling. An approach dealing with projecting and mapping plane curves onto a B-spline surface is presented. …
-
Feasibility Study of a Multi-Purpose Aircraft Concept with a Leading-Edge Cross-Flow Fan
… an Extremely Short Take-off and Landing (ESTOL) aircraft. The wing-embedded CFF performance analysis is mostly addressed from an aerodynamic perspective and focuses on using such AFC technology in the conceptual aircraft design process. In particular, the design trade study of an aircraft …
-
Signomial programming for aircraft design
Due to the coupled nature of aircraft system design, it is important to consider all major subsystems when optimizing a configuration. This, however, is easier said than done, particularly because each individual subsystem model can be arbitrarily complex. By restricting an optimization problem to …
-
Valuation techniques for commercial aircraft program design
This research considers the commercial aircraft design process from the perspective of program value. Whereas traditionally, the conceptual design of aircraft has often focused on minimum weight, or sometimes minimum cost, this approach demonstrates the feasibility and usefulness of design based on …
-
Global and Robust Optimization for Engineering Design
There is a need to adapt and improve conceptual design methods through better optimization, in order to address the challenge of designing future engineered systems. Aerospace design problems are tightly-coupled optimization problems, and require all-at-once solution methods for design consensus …
-
Multidelity approaches for design under uncertainty
… to account for their effects during engineering design to achieve robust and reliable systems. One approach is to represent uncertainties as random inputs to the numerical model of the system and investigate the probabilistic behaviour of the model outputs. However, performing optimization in …
Page 1 of 2