Aerospace Engineering Commons^™

Mapping Of Iva Spacesuit Mobility: Design Observations And Functionality, Gavin C. James, Ryan L. Kobrick, Victor Kitmanyen

Publications

The SUIT Lab at Embry-Riddle Aeronautical University is a joint student-faculty project utilizing multiple high altitude pressure garments to investigate suited crew capabilities within a spacecraft during simulated spaceflight missions. The testing environment within the SUIT lab includes the use of suits in a lowfidelity capsule cabin mockup with a horizontally situated launch-positioned chair simulator. Standard videography and analytical video software are used to determine levels of achievement in ergonomic range of motion and comfort design across multiple spacesuits. Comparative analysis and testing provide data supporting the requirement for the use of particular spacesuits inside proposed commercial launch vehicles. Results …

Suitability Testing For Possum Scientist-Astronaut Candidates Using The Suborbital Space Flight Simulator With An Iva Spacesuit, Pedro J. Llanos, Victor Kitmanyen, Erik Seedhouse, Ryan L. Kobrick

Publications

This paper evaluates key functional data parameters that must be considered for suborbital spaceflight participants wearing pressurized suits for intravehicular activity (IVA). Data parameters of an analog spacesuit worn in an analog flight environment were obtained from 40 civilian participants using the Suborbital Space Flight Simulator (SSFS) at Embry-Riddle Aeronautical University (ERAU) while donning Final Frontier Design’s (FFD) fully pressurized third-generation spacesuit as part of their training for Project PoSSUM (the Polar Suborbital Science in the Upper Mesosphere Project). The physiological data collected included: blood pressure, electrocardiograms, heart rate, grip strength, and skin temperature. These parameters were measured using a …

Human Factors For Small Net Habitable Volume: The Case For A Close-Quarter Space Habitat Analog, Victor Kitmanyen, Timothy J. Disher, Ryan L. Kobrick, Jason P. Kring

Publications

Increasing efforts in sending humans to Mars calls for greater considerations of the ways in which vehicle and habitat design can influence crew performance and behavioral health.

Time Optimal State Feedback Control With Application To A Spacecraft With Cold Gas Propulsion, Samuel J. Kitchen-Mckinley, Sergey V. Drakunov

Publications

A cold gas propulsion system is well suited to provide the required thrust for a small surveyor spacecraft operated near an asteroid or planetary surface. The cold gas propellant can obtained in-situ from local surface or atmospheric constituents. For small spacecraft, the cold gas system may be limited to only on-off control of the main tank where the generated thrust is directly dependent on the tank pressure. As such the thrust will slowly decrease as the propellant is expended. A state feedback, time optimal, control law is developed for a vehicle with propellant is expended. A state feedback, time optimal, …

Six Degrees Of Freedom From Six Degrees Of Separation: The History Of Flight Simulators, David Keck, Morgan Lopez

Publications

Some of today's advanced flight simulators have the capacity to provide pilots with experiences of six degrees of freedom: forward/backward, up/down, or left/right (or pitching, rolling, or yawing in either direction). These incredible devices are the product of over 100 years of design developments that come from a series of technological discoveries and historical events.

Design Of Variable Stiffness Composite Panels For Maximum Strength, Joel P. Hurley

Doctoral Dissertations and Master's Theses

The purpose of this research is to explore the design of variable stiffness composites and develop an automated framework to model, analyze and optimize these structures. Variable stiffness composites have been shown to exhibit increased strength and stiffness over traditional constant stiffness composites by tailoring fiber orientations for specific load conditions. This is achieved by allowing the fiber orientation to vary spatially across the design domain. Motivation for new design methods is driven by the recent advancements in composite additive manufacturing, such as automated fiber placement machines, which allow fiber reinforcements to be placed along prescribed trajectories during manufacturing. Through …

Numerical Study Of Mixing Of A Supercritical Jet In A Supercritical Environment, Neil Sullivan

Doctoral Dissertations and Master's Theses

A numerical simulation campaign is conducted to better elucidate flow physics and modeling requirements of a supercritical (SC) nitrogen jet injected into a tank of quiescent SC nitrogen. The goals of this work are twofold: to inform the design of injectors and combustion chambers for use in the direct-fired supercritical CO2 (s-CO2) power generation cycle and cryogenic liquid propellant rockets, and to investigate the extent to which meaningful flow characterization can be achieved with computationally expedient methods, using commercial software. Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES) approaches are used in STAR-CCM+ versions 10.06.010 and 12.02.011. Jet disintegration is …

Improved Ballistic Wind Prediction Using Projectile Tracking Data, William Arthur Kenney

Computational Modeling & Simulation Engineering Theses & Dissertations

The United States Air Force AC-130 gunships have been in operation since the Vietnam War and have seen frequent use during recent conflicts. They are able to employ gun weapon systems from above a target in a way that maximizes possible time on target. When firing, the gun operators must deal with miss distances caused by winds acting on the projectile in flight. Operators currently perform a “tweak” to predict a ballistic wind affecting fired rounds which is then used in the fire-control to correct for the real winds and bring shots onto target. This correction, a single-point wind prediction, …

Novel Layered Double Hydroxides-Hydroxyapatite/Gelatin Bone Tissue Engineering Scaffolds: Fabrication, Characterization, And In Vivo Study, Fateme Fayyazbakhsh, Mehran Solati-Hashjin, Abbas Keshtkar, Mohammad Ali Shokrgozar, Mohammad Mehdi Dehghan, Bagher Larijani

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Developing Porous Biodegradable Scaffolds through Simple Methods is One of the Main Approaches of Bone Tissue Engineering (BTE). in This Work, a Novel BTE Composite Containing Layered Double Hydroxides (LDH), Hydroxyapatite (HA) and Gelatin (GEL) Was Fabricated using Co-Precipitation and Solvent-Casting Methods. Physiochemical Characterizations Showed that the Chemical Composition and Microstructure of the Scaffolds Were Similar to the Natural Spongy Bone. Interconnected Macropores Ranging over 100 to 600 Μm Were Observed for Both Scaffolds While the Porosity of 90 ± 0.12% and 92.11 ± 0.15%, as Well As, Young's Modulus of 19.8 ± 0.41 and 12.5 ± 0.35 GPa Were …

Investigation, Modeling And Validation Of Digital Bridge For A New Generation Hot-Wire Anemometer, Karthik Kamalakar Joshi

Mechanical & Aerospace Engineering Theses & Dissertations

The Digital Bridge Thermal Anemometer (DBTA) is a new generation anemometer that uses advanced electronics and a modified half-Wheatstone bridge configuration, specifically a sensor and a shunt resistor in series. This allows the miniaturization of the anemometer and the communication between host computer and anemometer is carried out using serial or ethernet which eliminates the noise due to the use of long cables in conventional anemometer and the digital data sent to host computer is immune to electrical noise. In the new configuration the potential drop across a shunt resistor is used to control the bridge.

This thesis is confined …

A Low Cost Inflatable Cubesat Drag Brake Utilizing Sublimation, Adam Charles Horn

Mechanical & Aerospace Engineering Theses & Dissertations

The United Nations Inter-Agency Debris Coordination Committee has adopted a 25-year post-mission lifetime requirement for any satellite orbiting below 2000 km in order to mitigate the growing orbital debris threat. Low-cost CubeSats have become important satellite platforms with startling capabilities, but this guideline restricts them to altitudes below 600 km because they remain in orbit too long. In order to enable CubeSat deployments at higher release altitudes, a low-cost, ultra-reliable deorbit device is needed.

This thesis reports on efforts to develop a deployable and passively inflatable drag brake that can deorbit from higher orbital altitudes, thereby complying with the 25-year …

Development Of The Compact Jet Engine Simulator From Concept To Useful Test Rig, Henry H. Haskin

Mechanical & Aerospace Engineering Theses & Dissertations

NASA had a goal to develop a set of modeling tools for designing next generation civil transport aircraft with reduced noise, emissions and increased fuel efficiency by 2016. To verify the models, a database of aerodynamic and acoustic data was needed for an unconventional flying wing design that was predicted to meet the goals. A Compact Jet Engine Simulator (CJES) was needed as the jet source for the 5.8% scale model. Ultra-Compact Combustor Technology from the Air Force Research Laboratory was used to reduce the conventional burner acoustic test rigs down to the required scale size. The Air Force design …

Optimal Control Methods For Missile Evasion, Ryan W. Carr

Theses and Dissertations

Optimal control theory is applied to the study of missile evasion, particularly in the case of a single pursuing missile versus a single evading aircraft. It is proposed to divide the evasion problem into two phases, where the primary considerations are energy and maneuverability, respectively. Traditional evasion tactics are well documented for use in the maneuverability phase. To represent the first phase dominated by energy management, the optimal control problem may be posed in two ways, as a fixed final time problem with the objective of maximizing the final distance between the evader and pursuer, and as a free final …

Validation Of Adaptive Control Laws Using Optimization And Trajectory Sensitivity, Mario Luca Fravolini, Antonio Ficola, Fabio Radicioni, Tansel Yucelen, Ehsan Arabi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper it is proposed an easy-to-use verification and validation method for adaptive control laws that relies on time domain simulations. The problem is set as a trajectory falsification problem that is the search of closed loop trajectories that, starting from a set of admissible initial conditions, reach a set of unsafe states. The falsification is placed as a nonlinear optimization problem whose decision variables are the initial condition of the states and the uncertain parameters of the system. The falsification is performed iteratively using the local gradient of the sensitivity function derived from a linearized model of the …

A Decentralized Adaptive Control Architecture For Large-Scale Active-Passive Modular Systems, Benjamin C. Gruenwald, Ehsan Arabi, Tansel Yucelen, Animesh Chakravarthy, Drew Mcneely

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Decentralized control of large-scale active-passive modular systems is considered. These systems consist of physically interconnected and generally heterogeneous modules, where local control signals can be only applied to a subset of these modules (i.e., active modules) and the rest are not subject to any control signals (i.e., passive modules). Using a set-theoretic adaptive control approach predicated on restricted potential functions, we design decentralized command following control architectures for each active module such that they can effectively perform their tasks with strict performance guarantees in the presence of unknown physical interconnections between modules and module-level system uncertainties. The efficacy of the …

An Algorithm For Enlarging The Region Of Attraction Using Trajectory Reversing, Nilay Kant, Dhrubajit Chowdhury, Ranjan Mukherjee, Hassan K. Khalil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Trajectory reversing is a method commonly used for estimating the region of attraction of stabilized equilibria. Using a discrete set of points obtained by trajectory reversing, this paper presents an algorithm for estimation and mathematical representation of the region of attraction using convex hulls. Several two-dimensional examples are presented to illustrate the usefulness of the algorithm. The method provides larger estimates compared to that obtained by existing algorithms, but its main advantage lies in its applicability to higher-order systems. The mathematical representation of the region of attraction is useful in applying the Impulse Manifold Method, which was developed for stabilization …

Enlarging The Region Of Attraction Of Equilibria Of Underactuated Systems Using Sum Of Squares And Impulse Manifold Method, Dhrubajit Chowdhury, Nilay Kant, Ranjan Mukherjee, Hassan K. Khalil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents an algorithm to enlarge the estimate of the Region of Attraction of stable equilibria of underactuated systems. To achieve this, we use a combination of the Sum of Squares (SOS) method and the Impulse Manifold Method (IMM). Initially, the SOS method is used to optimize the control input u(x) in order to obtain an enlarged Region of Attraction. The IMM is then applied on enlarged Region of Attraction obtained using SOS to further enlarge it. The IMM is implemented using high gain feedback and to demonstrate the efficacy of our algorithm, we present simulation results where an …

Swing-Up Of The Inertia Wheel Pendulum Using Impulsive Torques, Nilay Kant, Ranjan Mukherjee, Hassan K. Khalil

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The swing-up control problem of the inertia wheel pendulum is revisited in this paper. As different from existing methods, purely impulsive control inputs are used for swing-up. A mathematical formulation of the problem indicates that swing-up can be achieved using impulsive inputs applied at two discrete time instants. Two different swing-up schemes are presented and validated using numerical simulations where the impulsive inputs are approximated by high-gain feedback. The results of numerical simulations establish a direct link between high wheel velocities during swing-up and control strategies that take the pendulum directly to the upright configuration. They also indicate that the …

Cruise Missile Integrated Air Defense System Penetration: Modeling The S-400 System, Michael Pelosi, Amie K. Honeycutt

International Journal of Aviation, Aeronautics, and Aerospace

This research determines improved flight-path routes that make maximum utilization of terrain-masking opportunities, and defending radar and missile system equipment performance and launch timing constraints, in order to avoid radar detection and tracking, and to mitigate subsequent missile shoot-down risks. The problem is formulated as one of constrained optimization in three dimensions. Advantageous solutions are identified using the A* Algorithm in conjunction with detailed equipment performance and constraint calculations and high-resolution digital terrain elevation maps. Topographical features in digital terrain are exploited by the algorithm to avoid radar detection and tracking. The model includes provisions for all-aspect/all-frequency radar cross section …

Identifying Design Parameters Controlling Damage Behaviors Of Continuous Fiber-Reinforced Thermoplastic Composites Using Micromechanics As A Virtual Testing Tool, Ditho Pulungan, Gilles Lubineau, Arief Yudhanto, Recep Yaldiz, Warden Schijve

Mechanical and Aerospace Engineering Faculty Research & Creative Works

In this paper, we propose a micromechanical approach to predict damage mechanisms and their interactions in glass fibers/polypropylene thermoplastic composites. First, a representative volume element (RVE) of such materials was rigorously determined using a geometrical two-point probability function and the eigenvalue stabilization of homogenized elastic tensor obtained by Hill–Mandel kinematic homogenization. Next, the 3D finite element models of the RVE were developed accordingly. The fibers were modeled with an isotropic linear elastic material. The matrix was modeled with an isotropic linear elastic, rate-independent hyperbolic Drucker–Prager plasticity coupled with a ductile damage model that is able to show pressure dependency of …