Engineering Commons^™

Modeling And Experimental Investigation Of Pre-Mixed Multi-Powder Flow In Fabricating Functional Gradient Material By Laser Metal Deposition Process, Wei Li, Jingwei Zhang, Sreekar Karnati, Yunlu Zhang, Frank W. Liou, Joseph William Newkirk, Karen M. Brown Taminger, W. L. Seufzer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser Metal Deposition (LMD) is an effective process to fabricate Functionally Graded Material (FGM) from pre-mixed powders. Since the supplied multi-powder directly affects the deposited FGM’s composition, investigation on Pre-Mixed Multi-Powder (PMMP) flow during LMD is greatly needed. This paper presents a comprehensive numerical PMMP flow model. By solving discrete particle force balance equations coupled with continuity equations and momentum equations for carrier gas, the dynamic behavior of PMMP flow through powder feeder tube and out of nozzle was calculated. With this model, the particle sizes of multi-powder were optimized to obtain considered FGM composition. To verify the modeling results, …

Elevated Temperature Microstructure Stability Of Slm 304l Stainless Steel, Tarak Amine, Joseph William Newkirk

Materials Science and Engineering Faculty Research & Creative Works

With time at temperature, changes in metallurgical structure can be expected for almost any steel or alloy. In stainless steels, the changes can be grain growth, carbide precipitation, ferrite decomposition, or embrittlement. These phenomena can significantly effect the properties of the steel and would potentially change the functionality of the component. Therefore, to determine component stability, the elevated temperature microstructure stability of additive manufacturing materials was studied. This work investigates the influence of different aging times of additive material stainless steels (304L) fabricated with the Selective Laser Melting (SLM) process on microstructure and mechanical properties. Microstructure and mechanical properties were …

Effect Of Sparse-Build Internal Structure On Performance Of Fused Deposition Modeling Tools Under Pressure, S. Meng, L. Mason, Gregory Taylor, X. Wang, Ming-Chuan Leu, K. Chandrashekhara, Mike Matlack, James Castle

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Two different approaches to design a sparse-build tool for fabrication by the fused deposition modeling (FDM) process are compared. One approach uses a 2D lattice structure and the other approach is inspired by topology optimization. Ultem 9085 is used as the material, and the amount of material used to build the tool is kept constant to ensure a fair comparison. A solid tool is also included in the comparison. The performance of the tool under uniform pressure is simulated using finite element analysis (FEA) and the accuracy of the FEA results is verified by comparing them with experimentally measured data …

Investigation Of Tensile Properties Of Bulk And Slm Fabricated 304l Stainless Steel Using Various Gage Length Specimens, Sreekar Karnati, I. Axelsen, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The complex solidification dynamics and thermal cycling during Selective Laser Melting process is expected to result in non-equilibrium material characteristics. There is an essential need for characterization techniques which are critical towards the estimation of anisotropies. The current investigation is targeted towards establishing tensile testing methodologies and their relation to differing gage lengths. Dog-bone shaped specimen designs with gage lengths of 1”, 0.3” and 0.12” were employed in this research. The characterization was performed on hot rolled-annealed 304 stainless and SLM fabricated 304L stainless. It was theorized that smaller gage length specimens would be instrumental in mapping material property anisotropy …

Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming-Chuan Leu, Greg Hilmas

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density is introduced in this paper. In this process, an aqueous paste of ceramic particles with a very low binder content (< 1 vol%) is extruded through a moving nozzle at room temperature. After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides. Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape. The same procedure is repeated for every layer until part fabrication is completed. Several sample parts for various applications were produced using this process and their properties were obtained. The results indicate that the proposed method enables fabrication of large, dense ceramic parts with complex geometries.

Modal Response As A Validation Technique For Metal Parts Fabricated With Selective Laser Melting, Joshua D. Pribe, Brian M. West, Michelle L. Gegel, Troy Hartwig, Toby Lunn, Ben Brown, Douglas A. Bristow, Robert G. Landers, Edward C. Kinzel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper investigates modal analysis as a validation technique for additively manufactured parts. The Frequency Response Function (FRF) is dependent on both the geometry and the material properties of the part as well as the presence of any defects. This allows the FRF to serve as a “fingerprint” for a given part of given quality. Once established, the FRF can be used to qualify subsequently printed parts. This approach is particularly attractive for metal parts, due to the lower damping as well as use in high-value applications where failure is unacceptable. To evaluate the efficacy of the technique, tensile specimens …

A New Wiretap Channel Model And Its Strong Secrecy Capacity, Mohamed Nafea, Aylin Yener

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a new wiretap channel (WTC) model with a discrete memoryless (DM) main channel and a wiretapper who noiselessly observes a fixed portion, of her choice, of the transmitted symbols, while observing the remaining transmitted symbols through another DM channel (DMC), is considered. The strong secrecy capacity of the model is identified. The achievability is established using the output statistics of random binning framework which exploits the duality between source and channel coding problems. The converse is derived by upper bounding the secrecy capacity of an equivalent model with the secrecy capacity of a DM-WTC. This result generalizes …

The Multiple Access Wiretap Channel Ii With A Noisy Main Channel, Mohamed Nafea, Aylin Yener

Electrical and Computer Engineering Faculty Research & Creative Works

A two-transmitter multiple access wiretap channel II (MAC-WT-II) with a discrete memoryless (DM) main channel is investigated. Two models for the wiretapper, who chooses a fixed-length subset of the channel uses and observes erasures outside this subset, are proposed. In the first model, in each position of the subset, the wiretapper noiselessly observes either the first or the second user's symbol, while in the second model, the wiretapper observes a noiseless superposition of the two symbols. Achievable strong secrecy rate regions for the two models are derived. The achievability is established by solving a dual secret key agreement problem in …

Investigation Of Heat-Affected 304l Ss Powder And Its Effect On Built Parts In Selective Laser Melting, Caitlin S. Kriewall, Austin T. Sutton, Ming-Chuan Leu, Joseph William Newkirk, Ben Brown

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Selective laser melting (SLM) is a powder bed based additive manufacturing process in which a layer of powder is laid over the surface of a substrate and a laser with sufficient energy is employed to selectively melt particles to build a part layer by layer. During the SLM process, dark smoke was observed coming off of the powder bed surface where the laser was interacting with powder. This phenomenon resulted from heat-affected powder that was visibly different than the base powder. Since the concentration of the heat-affected powder differs throughout the build chamber as a result of the recirculating argon …

Effect Of Powder Particle Size On The Fabrication Of Ti-6al-4v Using Laser Metal Deposition From Elemental Powder Mixture, Xueyang Chen, Lei Yan, Wei Li, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct Laser Metal Deposition (LMD) was used to fabricate thin-wall Ti-6Al-4V using the powder mixture of Ti-6 wt.%Al-4 wt.%V. Scanning electron microscopy (SEM), optical microscopy (OM) and energy dispersive spectroscopy (EDS) were employed to examine the chemical composition and microstructure of the as-deposited sections. Vickers hardness tests were then applied to characterize the mechanical properties of the deposit samples which were fabricated using pre-mixed elemental powders. The EDS line scans indicated that the chemical composition of the samples was homogenous across the deposit. X-ray diffraction (XRD) was used for the phase identification. After significant analysis, some differences were observed among …

Proposed Hybrid Processes For Part Building Using Fusion Welding And Friction Stir Processing, Megan A. Gegesky, Frank W. Liou, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

It has been shown that a hybrid laser additive manufacturing and friction stir processing can deposit components with forged-like structures. This paper reports a hybrid fusion welding and friction stir process to create parts with quality structures. Combining traditional fusion welding and friction stir processing techniques for non-weldable aluminum alloys could facilitate the joining of difficult geometries in manufactured parts. This research illustrates mechanical property changes for non-weldable and weldable aluminum alloys. The Vickers hardness, and microhardness in the case of AA5052-H32, tensile strength and corrosion resistance of four processing states: base material, fusion welded material, friction stir welded material, …

Practical Wired Digital Communications Link Analysis, Raymond Matthew Schmelzer

Dissertations and Theses

This thesis deals with the analysis of a Wired High Speed Serial Data Link (PAM2) which is commonly used throughout the data-communications and tele-communications industry. The goal of this study is to build a scalable simulation tool using Matlab that ultimately uses Receiver Bit Error Ratio (BER) as the metric for data link health. This study is also designed to aid in link specification development.

The Matlab and theoretical development is broken up into three sections being Transmitter (TX), Channel (Hs) and Receiver (RX). Realistic noise impairments can be added to each section along the signal path creating signal stresses …

Cubesat Model-Based Systems Engineering (Mbse) Reference Model –Model Distribution And Application –Interim Status #2, David Kaslow, Bradley Ayres, Michael Chonoles, Samuel Gasster, Laura Hart, Chris Massa, Rose Yntema

Small Satellite Conference

Model Based Systems Engineering (MBSE) is a key practice to advance systems engineering that can benefit CubeSat missions. MBSE creates a system model that helps integrate other discipline specific engineering models and simulations.

The International Council on Systems Engineering (INCOSE) established the MBSE Initiative to promote, advance, and institutionalize the practice of MBSE. The INCOSE Space Systems Working Group Challenge team has been investigating the applicability of MBSE for designing CubeSats since 2011.

Our application of MBSE uses System Modeling Language (SysML), a graphical modeling language, to model all aspects of a system either directly or through an interface with …

Project: Lunasonde, Jeremiah Pate

Small Satellite Conference

LunaSonde is a 6U CubeSat mission with the objective of exploring the moon while testing several new technologies. It is also a potential contender for the NASA CubeQuest Challenge. Although low earth orbit has been revolutionized by nanosatellite design, deep space/ lunar exploration have varied little from multimillion dollar missions. In order to expand the scope of planetary exploration, we have designed an adaptable lunar nanosatellite which leverages several new technologies such as 3-D printed construction, photonic integrated chips, and a miniaturized optical communication package. LunaSonde will analyze the lunar surface with a thermal and multispectral imager, demonstrating planetary exploration …

Enhancing Cubesat And Small Satellite Reliability Through Improved Thermal Management, Steven Isaacs, Diego Arias, Mike Hulse, Mark Lake, Derek Hengeveld

Small Satellite Conference

The interest in the use of CubeSat and small satellites for commercial, government and military applications continues to grow. Particularly in Low Earth Orbit, the successful deployment of commercial electronics has allowed dramatic reductions in cost and dramatic improvements in performance. These benefits leverage the R&D and production infrastructure of terrestrial electronics companies that dwarf the traditional space supply base. However, questions remain on the specific levels of reliability that can be achieved using hardware that was designed and tested for use in a very different environment compared to traditional space components that are designed for and tested to environmental …

Large Square-Loop Antenna Deployment From Cubesats, Angela Cleri, Ralen Toledo, Austin Fruithandler, Brandon Goudy, Jacob Mingear, Norman Fitz-Coy

Small Satellite Conference

The small-scale nature of CubeSats presents a challenge for researchers looking to integrate large antennas that are suited for experiments using very low frequencies (VLF, 3-30 kHz). Loop antennas hold several advantages over monopole and dipole voltage probes because they are not subject to the same size restrictions. Monopoles and dipoles have to be larger to achieve the same gain and performance as loop antennas. Conversely, loop antennas hold a disadvantage in that they require stiffeners to maintain the loop structure which poses challenges in both stowage and deployment. To address these challenges, the University of Florida has been developing …

Ors Responsive Manufacturing 6u Spacecraft, Jillian Marsh, Eric Stroka, George Moretti, Quinn Young, Jim Perry, Dean Wada, Matt Jeppesen, Matt Felt, Bryan Hansen

Small Satellite Conference

The Operationally Responsive Space Office is developing a small satellite capability and small satellite design specifically for advanced manufacturing and assembly methods for a semi-automated assembly and test facility. Designing a small satellite to be assembled and tested with this novel and innovative approach enables reduced costs, schedule, and risk. This presentation will discuss the implementation, unique design features, lessons learned, and challenges associated with developing for this new rapid-assembly capability as well as the unique benefits and challenges of assembly and test using automated, robotic systems. The presentation will also include discussions of the role that design-for-manufacturing, modular open …

Robust, Radiation Tolerant Command And Data Handling And Power System Electronics From Nasa Goddard Space Flight Center, Hanson Nguyen, James Fraction, Melyane Ortiz-Acosta, George Dakermanji, Bradford P. Kercheval, Amri Hernandez-Pellerano, Leonine S. Lee, David S. Kim, David S. Jung, Steven E. Meyer, Udayan Mallik, Kurt D. Rush, Faramarz Farid, James C. Olsen, Pietro A. Sparacino

Small Satellite Conference

In today's rapidly advancing technology roadmap for space applications there is an emphasis on completing missions faster and cheaper than previous large-scale missions at the National Aeronautics and Space Administration (NASA) such as the Lunar Reconnaissance Orbiter (LRO) or the Magnetospheric Multiscale (MMS) mission. As part of this effort, focus has shifted from using mostly radiation-tolerant or radiation-hardened parts to more commercial-off-the-shelf (COTS) components for missions that can last at least one year in orbit. However, there are some portions of a spacecraft's avionics, such as the command and data handling (C&DH) system and the Electrical Power Systems (EPS) that …

Energy-Cognizant Scheduling Of Store-And-Forward Communications With Multiple Priority Levels In Nanosatellite Systems, Cherry Y. Wakayama, Peter J. Yoo, Zelda B. Zabinsky

Small Satellite Conference

We derive an autonomous scheduling system for low earth orbiting store-and-forward communications nanosatellites (nanosats). Nanosats receive messages of different sizes and priorities, and the nanosat scheduling system determines when to deliver complete or partial messages to associated destinations. The optimal schedule considers nanosat limitations in terms of size, power, onboard data storage, energy capacity and contact time windows. In this paper, we first formulate a binary linear program to optimize a single-satellite resource-constrained message delivery schedule. Since a large-scale binary integer program is computationally intensive, we develop an approximation algorithm based on a time-indexed formulation and mean busy time objective …

Introduction To Nasa's Academy Of Aerospace Quality, Alice Smith, Jeffrey Smith

Small Satellite Conference

The NASA Academy of Aerospace Quality (AAQ) is an internet-based public domain forum of quality assurance-related educational modules for students and faculty at academic institutions targeting those involved in aerospace research, technology development, and payload design and development including Cube Sats, Small Sats, Nano Sats, Rockets and High Altitude Balloons. The target users are university project and research teams but the academy has also been used by K-12 teams, independent space activists, NASA contractors and other governmental agencies including those abroad. The interactive - web portal contains a curriculum structure of 50 diverse technical topics such as workmanship, systems engineering, …

Lean Satellite Concept, Filippo Graziani, Mengu Cho

Small Satellite Conference

In 2014, International Academy of Astronautics (IAA) initiated Study Group (SG) 4.18, "Definition and Requirements of Small Satellites Seeking Low-Cost and Fast-Delivery". Its objectives of the study group are to examine the definitions of small satellites, identify the requirements every satellite should follow and then reflect some of the findings to an ISO standard draft ISO/WD/20991, "Space systems - Requirements for Small Spacecraft" that is being developed recently at ISO/TC20/SC14. The purpose of the present paper is to present the latest findings in the SG activity especially in terms of small satellite definition.

During the SG meeting in 2014, a …

Design And Development Of A Multi-Mode Monopropellant Electrospray Mircropropulsion System, Steven P. Berg, Joshua L. Rovey

Small Satellite Conference

Multi-mode spacecraft propulsion is the use of two or more types of propulsive devices on a spacecraft that share some commonality in terms of either hardware or propellant. An example is the Mars Global Surveyor, which made use of hydrazine as both a monopropellant for attitude control and a bipropellant for primary maneuvering. Specific to this study is a multi-mode propulsion system making use of a high-thrust chemical mode and a high-specific impulse electric mode. Using these two modes can be beneficial in two primary ways. One way is by designing a mission such that the high-thrust and high-specific impulse …

Characterizing Chromatic Effects In Small Star Trackers, Tom Dzamba, John Enright, Doug Sinclair

Small Satellite Conference

No abstract provided.

Iitmsat: Innovative Packet Protocol And Concept Of Operations, Akshay Gulati, Sourbh Bhadane, Joseph Samuel, Harishankar Ramachandran, R. David Koilpillai

Small Satellite Conference

No abstract provided.

Microscope, A Cnes Microsatellite To Check Einstein Equivalence Principle, And Its Rf Equipments, Clement Dudal, Romain Mathieu, Yves André, Marie Vialard, Hervé Guillon, M. Fernandez, Anis Latiri, G. Guillois, Y. Richard, P. Bataille

Small Satellite Conference

No abstract provided.

Targeting All Of Stem In The Primary School : Engineering Design As A Foundational Process, Lyn English

2009 - 2019 ACER Research Conferences

With the increased national and international focus on advancing STEM education, it is important to ensure all of its disciplines are represented in the curriculum. To-date, the STEM acronym has been used largely in reference to science, with less emphasis on the remaining disciplines – especially engineering. Yet engineering design, a core component of engineering education, is now seen internationally as a foundational process linking the STEM disciplines, not just confined to engineering. Engineering concepts, design processes, representing, modelling, and innovative design-based problem-solving are all featured within the new Design and Technologies Curriculum. This paper will explore the nature and …

Development Of A Low-Flying Cubesat Mission For F-Region Characterization, Jonathan Black, Gregory Earle, Robert Mcgwier, Anthony Wolosik

Small Satellite Conference

Plasma irregularities in the F-region (200-800 km) of the night-time equatorial ionosphere have been shown to significantly influence the performance and reliability of space borne and ground based radio communication systems. Equatorial Spread-F (ESF) episodes may cause the disruption of satellite operations, communications, and navigation due to backscatter and radar scintillation. Current records of rocket, satellite, and radar data are not of sufficient quantity to allow for accurate models and predictions of the spectrum of irregularities. To provide a better understanding and predict F-region phenomena that may disrupt communications, it is important to perform in situ, or local, real-time measurements …

The Conceptual Design Of Cubesat Based System For Gnss Radio Occultation/Reflective Mission, Jer Ling, Chen-Tsung Lin

Small Satellite Conference

The Global Navigation Satellite System (GNSS) Radio Occultation/Reflective (RO/R) instrument collects global atmospheric data and oceanic wind speed data for weather prediction and climate researches. This paper proposes the conceptual design of the satellite constellation and the satellite to realize the GNSS-RO/R mission based on the cubesat platform, with the goal to achieve cost effectiveness and minimum deployed schedule. The cubesat considered in the study is 6U and within 10 kilogram. The proposed innovative constellation consists of 12 (minimum required) plus 6 (backup) satellites on three 500 km altitude sun synchronous planes, 6 satellites even phasing on each plane. It …

Miniaturized Phonon Trap Timing Units For Pnt Of Cubesats, Mina Rais-Zadeh, Adam Peczalski, Serhat Altunc, Yun Zheng, Obadiah Kegege, Harry Shaw, Greg Heckler

Small Satellite Conference

This research is directed towards development of a chip-scale timing unit (clock) to be used in new systems that aim to improve the quantity and quality of data transmittal from small spacecrafts. The quantity and quality of data transmission are directly influenced by the speed and accuracy of the on-board clock. NASA roadmap identifies major technical challenges for space clocks using current technologies (i.e., quartz resonators), namely sensitivity to on-board thermal environment conditions and susceptibility to g-force, and ionizing radiation effects. The timing units developed under this project will enhance the current Small Satellites capabilities. With this technology Small Sats …

Modular Payload-Centered Cubesat, Saleh Al-Shidhani

Small Satellite Conference

CubeSats gained a lot of popularity recently after many successful missions and due to the availability of pico-components for these satellites. Although miniaturizing the electronic circuits, sensors and attitude control hardware are progressing very well, there are other components that cannot be miniaturized such as imaging lenses while maintaining spacial resolution. As results, bigger CubeSats were introduced. To maintain smaller size we developed a new Cubesat structure that's likely to reduce the size by 50%. The frame structure design offers the demanded rigidity around the payload and surrounded with eight slots for other components. the slots offer direct access to …