1) Master's Thesis

Methodology of a Parametric Tow-Steered Composite (TSC) Shape Function on a Wing Planform Design Space

• The inclusion of this technology in an aircraft structure leads to structural and system-level benefits, such as structural weight reduction, passive load alleviation and improved fuel burn efficiency.
• Traditional wing skins contain stacks of laminate layers with uniaxial fibers, which are characteristic of constant material properties, such as sectional stiffness.
• With tow-steered composites, the orientation of the fibers is allowed to vary continuously throughout each panel of the laminate layer, allowing for sections of variable stiffness.
• This allows for the aircraft designer to conduct aeroelastic tailoring of the wing, which manipulates the sectional stiffness properties of the wing for passive load alleviation, higher flutter/divergence airspeeds, reduced structural weight and reduced stress concentrations.
• This methodology will involve the performance of trade studies on aircraft wing design variables, such as aspect ratio and planform area, and how they affect the composition of the fiber orientation throughout the wing. The tow-steered composite shape functions will be modeled in an in-house ASDL toolkit called the Rapid Airframe Design Environment (RADE) and a system-level analysis will take place in the Flight Optimization System (FLOPS).

2) Structural Analysis and Layout of

unconventional Aircraft Configurations

Aurora d8 x-plane configuration

boeing ttbw x-plane configuration

• The overall goal of this research is to run a systems analysis on a multitude of unconventional aircraft configurations in order to assess their feasibility and viability in the future aircraft market of 2030.
• For the structures team, there is a goal to get the structural layout for unconventional aircraft configurations in a way that is modular and adapts to different aircraft OpenVSP outer mold lines (OMLs) through the use of Python logic. The main tool that completes this task is the Rapid Air-frame Design Environment (RADE), which is an in-house ASDL tool at Georgia Tech.
• This structural layout will eventually lead to an independent structural weight estimation and preliminary phases of structural analysis. The structural weight obtained here will be used to create surrogate models of structural wing weight as a function of appropriate design variables
• This would be fed into the "Environmental Design Space" (EDS) to conduct a full systems analysis on the vehicle.
• The first unconventional configuration was the Aurora D8 "double bubble" concept, which has a wide fuselage with Y-joints and tension rods along the longitudinal length of the fuselage.
• The second unconventional configuration was the Boeing Transonic Truss-Braced Wing (TTBW), which has a high aspect ratio wing,. This is supported by the addition of a jury and strut connected from the wing to a gear pod under the fuselage.

GRAND CHALLENGES (Projects 3 & 4)

3) D.E.L.I.V.E.R.

Decomposition of a Lunar In-Space Vehicle for Robotic Assembly

STUDY OBJECTIVE

• Our Grand Challenge was to approach the concept of In-Space Assembly (ISA) from a technology pull point-of-view
• We studied the impact of ISA technology on the assembly logistics of an artificial gravity station in cis-lunar space

PROBLEM APPROACH

• Enabling manned long-duration Lunar missions requires developing new systems and architectures
• Spinning Wheel-type architecture allows a larger habitable space, while achieving the desired Gravity Level
• Formulated problem as the combined optimization of:
  • Piece Division
  • Delivery Allocation
  • Assembly Sequence
• The AG system is composed primarily of truss pieces and habitat pieces
• The assembly sequence is broken down into five states
  • Standby / In orbit
  • Unpackaging
  • Positioning and Welding
  • Inspection
  • Assembled
• Moon exploration goals and crew health challenges in deep space offer rationale for a large, artificial gravity space station in cis-Lunar space in the medium term future
• The need for advanced In-Space Assembly capabilities to assemble such a large system and the complex logistics involved justify an optimization problem approach
• Our team developed a Mixed Integer Programming formulation of the piece division, launch allocation, and assembly sequencing for a sized AG station
• Using advanced In-Space Assembly, “sci-fi” concepts such as a large artificial gravity station can become a reality
• It is possible to encode the complex logistics involved in assembling this system into a MIP formulation
• The model developed is:
  • Flexible to different CONOPS, delivery systems, delivery schedules, and ISA capability levels
  • Deterministic: with enough time and resources, exact optimal solutions can be found
  • Allows more precise constraints than can be defined using stochastic optimizers
  • Expandable to potential new trade-offs future stakeholders will have

4) S.W.I.F.T.

Aero-Structural Weight Considerations for an Integrated Framework Trade Space

study objective

• Development of a framework to study advanced configurations with structural aero-elastic considerations
• Formulation of SWIFT, an aero-structural analysis framework for the wing on a subsonic aircraft to predict structural weight

Conceptual design

preliminary design

Case study on NASA CRM

• SWIFT is a multidisciplinary feasible (MDF) framework that aims to accurately predict the structural weight of the CRM wing under aero-elastic conditions
  • Non-proprietary test bed for subsonic regime
  • Only use aircraft models with proven validation data
  • No dynamic loads considered within SWIFT (computationally expensive)
• Goal is to incorporate aspects of preliminary design earlier on in conceptual design, such as accurate loads generation, to populate historical data for advanced concepts
• Comparison of single pass structural weight prediction results to EDS results
  • Component thicknesses are optimized to meet the structural requirements
  • Structural weight results from RADE differ from EDS results
• Proper calculation of jig shape is key to manufacturing considerations and detailed design later on

5) hybrid wing-body trade space exploration

Hybrid wing-body vehicles offer significant performance and efficiency increases over traditional tube-and-wing aircraft. However, the cost and risk associated with developing an all-new architecture for a commercial aircraft dictates that the manufacturer must make a significant effort to ensure that the resulting vehicle will out-compete all other aircraft in its class, especially in terms of fuel burn and acquisition price.

My team analyzed the performance and capabilities of a 300-passenger large twin-aisle hybrid wing-body aircraft. After determining that there were no possible avenues to meet all of our desired performance targets by altering the characteristics baseline vehicle, we proceeded with a TIES analysis to evaluate the potential of technology infusions to open up the design space.

First, we created a series of surrogate models in order to remove the need for repeated costly queries to the modelling environment. Next, we investigated the potential impact of a large number of technologies on the baseline design. In order to manage the intractable technology space, we employed a multi-objective genetic algorithm to select a number of Pareto-optimal design alternatives under certain constraints. Finally, a favored design was selected from the population using a variety of multi-attribute decision making techniques.

Our final technology package introduces damage arresting stitched composites on the fuselage and wing of the aircraft, which reduce empty weight, and thus acquisition price, and enable the construction of a complex fuselage shape. A compressor intercooler is added to the engine core in order to drastically reduce harmful emissions and ensure the aircraft design is robust against any future NO_x regulations. Finally, hybrid laminar flow control was added to the wing using discrete roughness elements, which significantly improves the cruise performance of the vehicle, and thus reduces fuel burn and operating cost. The result is a vehicle that performs better than any on the market today at a lower cost, which we believe is significant motive to prompt the development of said vehicle.

6) sizing & synthesis tool of a fixed-wing aircraft

mission 1 - military fighter aircraft

mission 2 - pilot trainer aircraft

excel tool User interface

CONCEPTUAL DESIGN OF A FIXED-WING AIRCRAFT

Sizing and Synthesis through Constraint Analysis and Mission Analysis

The main aspect of the aircraft design project life cycle explored is the sizing and synthesis of the vehicle. A design tool has been created in Microsoft Excel that is capable of properly sizing an aircraft to an efficient takeoff weight while also satisfying the mission objectives. Two different missions have been created in the same Excel file to test the versatility of the tool, where both missions undergo a constraint analysis and a mission analysis.

In the constraint analysis, the aircraft satisfies a set of phases in its given mission profile. Appropriate cases are incorporated into the tool, allowing for the output of the thrust loading (T/W) and wing loading (W/S). Once these parameters are found, the mission analysis can be conducted to figure out the fuel burn consumption of the vehicle during this mission. The thrust loading and wing loading retrieved from the constraint analysis become inputs for the mission analysis, allowing for the calculation of the weight fraction of the aircraft at the end of each mission phase. At this point, the takeoff weight can be calculated, leading to the required fuel weight. This process iterates until the required fuel weight falls within a specified tolerance to the fuel weight available.

The first mission will benchmark a military fighter aircraft against the concept and design of a F86-L Sabre fighter aircraft. This design must satisfy mission phases provided in the project description that would typically be conducted by a fighter aircraft. By the end of the sizing and synthesis process, the goal is to create a fighter aircraft with a conceptual design that matches the actual design of the F86-L Sabre fighter aircraft. Certain key characteristics, such as the predicted maximum required thrust at sea level and the predicted wing area, will be compared to the actual result to test the accuracy of the Excel tool.

The second mission will size a pilot trainer aircraft through a similar process to the benchmark exercise. In this case, the objective is to create a two-person crew aircraft that has the capabilities of a typical combat fighter aircraft and can complete similar missions, which is used to teach a new pilot how to fly in real-life conditions. There are currently no 2-seat pilot training aircraft, such as the F-22 or F-35, that have the capabilities to satisfy the design objectives. The F-16 is the current model of this training mission, but needs to have a suitable replacement for when it is no longer used for this task. This aircraft will also undergo a constraint analysis and a mission analysis, but the main distinction is that an engine must be selected for this aircraft, which can satisfy all mission objectives. This training aircraft should train the pilots in basic aircraft control, airmanship, formation, cockpit resource management and many other key aspects discussed in the project description.