Organizational Unit:

Aerospace Systems Design Laboratory (ASDL)

Permanent Link

https://hdl.handle.net/1853/70744

Parent Organization

Organizational Unit

Daniel Guggenheim School of Aerospace Engineering

ArchiveSpace Name Record

https://finding-aids.library.gatech.edu/agents/corporate_entities/1135

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Publication Search Results

Now showing 1 - 10 of 101

Hypersonics Research at ASDL

(Georgia Institute of Technology, 2007-02-26) Osburg, Jan ; Mavris, Dimitri N.
A Framework for Collaborative Design in Engineering Education

(Georgia Institute of Technology, 2007-01) Jiménez, Hernando ; Mavris, Dimitri N.

The Collaborative Design Environment (CoDE) is a dedicated collaborative design facility aimed at enhancing design team communication by supporting collocated system and discipline experts with analysis tools, design applications and various technologies. A generalized model of collaborative design offering flexibility and concurrently addressing the environment and the process as complementary counterparts is proposed. A detailed process was constructed by strategically aligning pertinent models of collaborative design from a variety of fields. The process clearly describes how technological affordances in the CoDE can be used to address the collaborative design challenges and leverage its advantages. This process was successfully implemented by a team of undergraduate aerospace engineering students participating in the 2006 AIAA aircraft design competition. The process, the environment and the generalized model serving as a flexible reference frame constitute a framework for collaborative design.
Niched-Pareto Genetic Algorithm for Aircraft Technology Selection Process

(Georgia Institute of Technology, 2006-09) Patel, Chirag B. ; Kirby, Michelle Rene ; Mavris, Dimitri N.

Design of any complex system entails many objectives to reach and constraints to satisfy. This multi–objective nature of the problem ensures that the technology solution is always a compromise between conflicting objectives. The purpose of this paper is to demonstrate the application of Niched Pareto genetic algorithm as a relatively fast and straightforward method for obtaining technology sets that are distributed along the Pareto frontier in objective space. In this implementation, the genetic algorithm is wrapped around a technology evaluation environment to efficiently evaluate various technology combinations. Some of the major challenges include formulation of Pareto domination tournament and sharing function of Niched Pareto genetic algorithm for a technology selection problem, extracting Pareto front from population of the final generation and visualizing the results.
A Framework for Determination of the Weak Pareto Frontier Design Solutions under Probabilistic Constraints

(Georgia Institute of Technology, 2006-09) Ran, Hongjun ; Mavris, Dimitri N.

The design of complex systems such as aircraft or missiles requires the synergy of multiple disciplines. The design quality must ultimately be assessed by multiple criteria that often can not be optimized simultaneously. Therefore, in a less restrictive sense the Weak Pareto Frontier (WPF) in the objective space and the corresponding design solutions must be found because the WPF includes more compromised solutions than the conventional Pareto frontier. Real-world decisions are usually made in a state of uncertainty. Most often the effects of uncertainties are embodied in the probabilistic constraints (PC) that usually must be satisfied jointly. The combination of these issues requires a new framework to combine separately developing multidisciplinary optimization, multi-objective optimization, and joint probability assessment methods together, to solve a joint probabilistic constraint, multi-objective, multidisciplinary optimization problem and find the WPF solutions. The purpose of this paper is to provide such a framework. This framework starts with constructing fast and accurate surrogate models of different disciplinary analyses in order to reduce the computational time and expense to a manageable level and obtain trustworthy probabilities of the PC’s and the WPF. A hybrid method is formed here that consists of the second order response surface methodology (RSM) and the support vector regression method (SVR) capturing the global tendency and local nonlinear behavior, respectively. The parameters of SVR to be pre-specified are selected using practical methods and a modified information criterion that makes use of model fitting error, predicting error, and model complexity information. Then a neighborhood search method based on Monte Carlo simulation is provided to find valid designs that are feasible and consistent for the coupling variables featured in a multidisciplinary design problem. Two schemes have been developed. One scheme finds the WPF by finding a large enough number of valid design solutions such that some WPF solutions are included in them. Another scheme finds the WPF by directly finding the WPF of each consistent design zone that is made up of consistent design solutions. Then the probabilities of the PC’s are estimated, and the WPF and corresponding design solutions are found. A simple yet typical aircraft design problem is solved to demonstrate the feasibility of this framework. The results show that the method to select the pre-specified parameters of SVR works well, the hybrid surrogate models are fast and accurate, and both neighborhood search schemes can find the WPF.
Analyzing Technology Interactions

(Georgia Institute of Technology, 2006-09) Patel, Chirag B. ; Mavris, Dimitri N.

Technology selection is a crucial step in the design of new complex systems. When many technologies are to be selected from a large pool of available technologies, it is very important that the interactions among these selected technologies are accounted for while assessing their impact on the system. This paper will discuss some of the intricacies involved in technology interactions and current method of Technology Constraint Matrix used to account for them. The advantages and limitations of this method are discussed and a new approach to analyze technology interactions based on the principles of Graph Theory is introduced.
Design and analysis of supersonic business jet concepts

(Georgia Institute of Technology, 2006-09) Rallabhandi, Sriram Kishore ; Mavris, Dimitri N.

Supersonic business jet design is a complex process to balance highly stringent environmenta requirements in addition to the usual performance measures. Conceptual aircraft designs obtained by employing simplified analyses would be compromised in some respect when the concept is transferred to further stages of design. To overcome this problem, improved analysis methods for conceptual aircraft design are developed in this study. Geometry is parameterized using many shape parameters to create any arbitrarily complex aircraft shape. The aerodynamic flow field near the aircraft is obtained in an automated fashion using three dimensional panel methods. Sonic boom propagation is carried out considering atmospheric variations, thermo-viscous absorption, molecular relaxation and diffusion phenomena. The optimization results obtained elsewhere using simple linear methods are analyzed using the methods developed here and the responses are compared. Shortcomings of the traditional approaches are discussed and future work using these improved methods is suggested.
A New Approach for Incorporating Computational Fluid Dynamics into Sonic Boom Prediction

(Georgia Institute of Technology, 2006-06) Rallabhandi, Sriram Kishore ; Mavris, Dimitri N.

A new approach for the inclusion of Computational Fluid Dynamics flow solutions into predicting sonic boom signatures is developed. Using existing CFD tools, a near-field flow solution is obtained over the surface of a computational cylinder a certain distance away from the aircraft longitudinal axis. Near-field to far-field multipole matching methodology is performed to calculate the corrected far-field without resorting to unnecessary numerical procedure of calculating the multipole coefficients. The analytical derivation is provided and some results are presented. The results obtained using this approach do not completely match with those obtained using earlier approaches. This is to be investigated in future work.
A System-of-Systems Design of a Guided Projectile Mortar Defense System

(Georgia Institute of Technology, 2006-06) Massey, Kevin C. ; Heiges, Michael W. ; DiFrancesco, Ben ; Ender, Tommer Rafael ; Mavris, Dimitri N.

A System-of-Systems design methodology is used to evaluate tradeoffs in the design of a guided bullet system for mortar defense. Guided bullets were designed to match the calibers of four different existing auto guns and were modeled in a six degree of freedom simulation. A bullet guidance system was developed based on proportional navigation and several control actuation schemes were modeled. The system simulation was setup to perform Monte Carlo analyses with noise models for various subsystems such as the gun controller and radar. Ranges of gun accuracies and ranges of radar noise were used to create a design space which also included the variation in gun caliber. A design of experiments approach was used to determine the simulation cases that needed to be run to map out the design space. Based on more than half a million independent simulations, a metamodel of the design space was created to capture the interactions between the gun, the projectiles, and the radar. This metamodel allows the user to rapidly evaluate the impact of design tradeoffs and to determine the best system based on his chosen metrics. Available metrics include, cost, weight, defended area, and combinations of the three. Initial results indicate that feasible designs for a guided bullet system are possible within the design space.
Strategies for integrating models of interdependent subsystems of complex system-of-systems products

(Georgia Institute of Technology, 2006) Weston, Neil R. ; Balchanos, Michael G. ; Koepp, Michael R. ; Mavris, Dimitri N.

The Office of Naval Research has established a need for improved design and analysis methods for the next generation of naval surface combatants. The Aerospace Systems Design Lab (ASDL) has initiated the Integrated Reconfigurable Intelligent Systems project to address design issues associated with the future systems. A goal of this program is to define preliminary approaches for developing an integrated modeling and simulation environment for complex systems. Since such systems are heterogeneous, dynamical and interdependent we suggest that a system-of-systems multidisciplinary approach is most appropriate for investigating and executing solutions. An integration methodology employing innovative techniques and a framework of tools that can be used to couple disparate models and simulations is presented. Methods for validating the final product to justify the selected approach and demonstrate a proof of concept for the integrated model are also discussed.
Development of a Collaborative Capability-Based Tradeoff Environment for Complex System Architectures

(Georgia Institute of Technology, 2006-01) Biltgen, Patrick Thomas ; Ender, Tommer Rafael ; Mavris, Dimitri N.

The design of complex systems in the presence of changing requirements, rapidly evolving technologies, and design uncertainty continues to be a challenge. Furthermore, the design of future platforms must take into account the interoperability of a variety of heterogeneous systems and their role in a larger "system-of-systems." To date, methodologies to address the complex interactions and optimize the system at the macro-level have lacked a clear direction and structure and have largely been conducted in an ad-hoc fashion. Traditional optimization has centered around individual vehicles with little regard for the impact on the overall system. A key enabler for reduced cost and cycle time is the ability to rapidly analyze technologies and perform trade studies using a capability-based approach. While many entities have expressed a desire to perform capability-based design, the need for a structured discipline exists. This research will examine how collaboration for the design of such systems-of-systems can be enabled through the use of surrogate models and will demonstrate a top-down analysis methodology for the evaluation of systems and technologies with respect to desired capabilities. A technique for inverse design where any variable can be treated as an independent variable is made routine through the structured use of surrogate models and probability theory. For the testbed demonstration, a depoliticized, notional scenario was postulated to develop a testbed environment in which humanitarian aid and supplies must be delivered to forward-deployed troops for dispersal in a host country under fire.