| Integrated Multi-Aperture Sensor and Navigation Fusion |
Feb 2010 |
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| Authors:
Andrey Soloviev; Jimmy Touma; Timothy Klausutis; Mikel Miller; Adam Rutkowski; Kyle Fontaine; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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 | The integration of vision sensors and inertial navigation system (INS) can enable precision navigation capabilities in the absence of GPS. Inspired from biological systems, a multi-aperture vision processing system allows for accurate self-motion (egomotion) estimation by observing optical flow across all apertures. The multi-aperture approach is particularly well suited for resolving motion-ambiguity by providing a wide field of regard for detecting and tracking visual features (optical flow). This paper presents ... |
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| Microstructural Design & Optimization of Highly Filled Epoxy Based Composites |
Nov-2009 |
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| Authors:
Bradley White; Jennifer L Jordan; D W Richards; Jonathan E Spowart; Naresh N Thadhani; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The dynamic mechanical properties of multi-constituent particulate composites, consisting of individual Ni and Al particles dispersed in an epoxy matrix are investigated in this study. Properties of such composites depend on the mechanical and physical properties of the individual components; their loading density; the shape and size of the particles; the interfacial adhesion; residual stresses; and matrix porosity. These multi-phase particulate composites systems, particularly those with high fill densities, have ... |
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| Autonomous Aerodynamic Control of Micro Air Vehicles |
19 Oct 2009 |
72 pages |
| Authors:
Gregg Abate; Kelly Stewart; Judson Babcock; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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 | This effort helped to solidify the linkage between the aerodynamic and guidance and control aspects of micro air vehicles. Micro air vehicles are characterized by small vehicle size (O 10 centimeters), low flight speeds (O 10 meters per second), and low Reynolds number (O 10,000 - 100,000). These micro air vehicles (MAVs) are unique in the fact that they are inherently multi-functional systems. That is, sub-systems within the MAV perform ... |
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| Evaluation of the Haltere as a Biologically-Inspired Inertial Rate Sensor |
Mar-2009 |
16 pages |
| Authors:
R A Thompson; M F Wehling; J E Evers; W E Dixon; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Since as early as the 1940's, specialized structures on dipteran insects have been recognized as necessary for inertial measurement associated with basic flight stability. These structures, called halteres, have been suggested to act as vibrating structure gyroscopes, measuring strains proportional to Coriolis accelerations. As a miniature, robust means for stabilizing flight, this biological inertial measurement system is not only of interest to biologists, but also to designers of biomimetic robotic ... |
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| Optic Flow for Enhanced Navigation and Seeker Exploitation (OFFENSE) |
Mar-2009 |
4 pages |
| Authors:
Jimmy E Touma; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Modern navigation systems rely heavily on the Global Positioning System (GPS) to correct inertial measurement unit (IMU) error drifts. However, due to unreliability og GPS in certain scenarios, there is a great desire to create an inexpensive navigation solution to augment GPS based navigation. Vision-aided navigation is such a solution where information from captured imagery can supplement inexpensive on-board IMUs in bounding navigational errors that arise from IMU drifts. Optical ... |
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| Experimental and Theoretical Investigation of the High-Pressure Behavior of Concrete |
01-Sep-2008 |
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| Authors:
Oana Cazacu; Martin J Schmidt; Mark L Green; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The results of an experimental study aimed at characterizing the behavior of concrete for high confining pressures (up to 500MPa) are reported. The main characteristics of the response under deviatoric conditions are quasi-linearity in the elastic regime, stress-path dependency, and gradual change from compressibility to dilatancy under increasing deviatoric stress. By performing the cyclic triaxial compression tests with several load-creep-unload and reload cycles, the time influence on the overall behavior ... |
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| Numerical Modeling of Heterogeneous High Explosives |
01-Sep-2008 |
32 pages |
| Authors:
Christopher M Engelhardt; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| This report contains a numerical algorithm for modeling the detonation and explosion of a heterogeneous mixture of high explosive and small metal particles. The simulation examines a spherical explosive design with a mixture of nitromethane as the high explosive and steel as the metal particles. The algorithm provides a computational model of the detonation and explosion by producing position, velocity, and temperature profiles for the metal particles over time. For ... |
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| Mechanical Properties of EPON 826/DEA Epoxy |
26-Jul-2008 |
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| Authors:
Jennifer L Jordan; Jason R Foley; Clive R Siviour; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Polymers are becoming increasingly used in aerospace structural applications, where they experience complex, non-static loads. Correspondingly, the mechanical properties at high strain rates are of increasing importance in these applications. This paper investigates the compressive properties of Epon 826 epoxy resin cured with diethynolamine (DEA) across strain rates from 10(-3) to 10(4) s(-1). Specimens were tested using an Instron mechanical testing machine for static loading, traditional split Hopkinson pressure bars ... |
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| Modular Advanced Fuze Interface Architecture (MAFIA) |
JUN 2008 |
22 pages |
| Authors:
Jason R. Foley; Matthew W. Bridge; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| OUTLINE: Purpose * What This is Not * Fuze Architectures and DoD Acquisition (current approach - modular, open systems) * Why This Program? Why Now? * Distributed Fuzing (perceived benefits - argument against) * Lessons Learned * MAFIA Approach * Summary * Questions. |
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| Polynomial-Time Identification of Optimal Robust Network Flows Under Certain Arc Failures (Preprint) |
JUN 2008 |
12 pages |
| Authors:
Clayton W. Commander; Vladimir Boginski; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Network flow problems have a wide variety of important applications in many areas. Although deterministic formulations of these problems are well-studied, in many practical situation one has to deal with uncertainties associated with possible failures of network components (e.g., each arc has a probability of failure). Formulations and optimal solutions of these problems need to be adjusted to take into account these uncertainty factors. The main difficulty arising in addressing ... |
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| Multifunctional Particulate Composites for Structural Applications (PREPRINT) |
MAY 2008 |
11 pages |
| Authors:
Jennifer L. Jordan; D. W. Richards; Jonathan E. Spowart; Bradley White; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Particulate composites consist of individual particles of one material dispersed throughout and held together by a polymer binder. The mechanical and physical properties of the composite depend on the mechanical and physical properties of the individual components; their loading density; the shape and size of the particles; the interfacial adhesion; residual stresses; and matrix porosity. Highly-loaded particulate composites are multi-phase systems that have not typically been studied rigorously, to date. ... |
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| Re-Visiting 1-D Hypervelocity Penetration (Preprint) |
01-Apr-2008 |
13 pages |
| Authors:
David E Lambert; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Classical, one-dimensional theory of hydrodynamic penetration is used as the basis of establishing simplified analytical relationships describing energy, momentum, and power deposition during hypervelocity impact events. A concise overview of the 1-D model is given followed by a select grouping of terms into relationships that offer first-order criteria for making engineering design considerations on relevant applications and assist in the analysis of experimental observations. Momentum, energy, and power deposition are ... |
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| Moisture Effects on the High Strain-Rate Behavior of Sand (Preprint) |
01-Apr-2008 |
31 pages |
| Authors:
Weinong Chen; Bo Song; Bradley E Martin; Stephen A Akers; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The effects of moisture content on the high strain rate mechanical properties of fine grain sand were characterized with a split-Hopkinson pressure bar. A controlled loading pulse allowed the sample to acquire stress equilibrium and a constant strain-rate of 400 s(exp -1). The sand specimen confined in a hardened steel tube, had a dry density of 1/50 g/cm(exp 3) with moisture contents varied from 3% to 20% by weight. Experimental ... |
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| Positrons, Quantum Crystals, and Nanoparticles (Oh My!) - Quantum Mechanics in Action at the USAF |
APR 2008 |
61 pages |
| Authors:
C. M. Lindsay; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| CONCLUSIONS: Solid parahydrogen produced by Rapid Vapor Deposition is amenable to Polarization Spectroscopy: Facilitates the assignment of the crystal field fine structure in the spectra of rotating dopants; * Sheds light on cluster formation in doped parahydrogen samples; * Provides new insight into the annealing behavior of the solid parahydrogen produced by RVD; * Electron and Positron irradiation of solid hydrogen presently underway. |
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| Dimensionality Reduction and Information-Theoretic Divergence Between Sets of Ladar Images |
MAR 2008 |
13 pages |
| Authors:
David M. Gray; Jose C. Principe; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| This paper presents a preliminary study of information-theoretic divergence between sets of LADAR image data. This study has been motivated by the hypothesis that despite the huge dimensionality of raw image space, related images actually lie on embedded manifolds within this set of all possible images and can be represented in much lower-dimensional sub-spaces. If these low-dimensional representations can be found, information theoretic properties of the images can be exploited ... |
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| Benchtop Insensitivity: First Steps with Shocked PETN |
JAN 2008 |
22 pages |
| Authors:
William K. Lewis; Mario E. Fajardo; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| "Insensitive Munitions (IM) are conventional weapons and ordnance that fulfill their performance objectives while minimizing collateral damage if exposed to stimuli including fires, impact and shock threats." "The statutory requirement for IM is set forth in U.S. Code, Title 10, Subtitle A, Part IV, chapter 141, Section 2389..." ... Department of Defense Acquisition Manager's Handbook for Insensitive Munitions, Jan 2004, Rev 1. |
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| Biological Inspiration for Agile Autonomous Air Vehicles |
01 NOV 2007 |
15 pages |
| Authors:
Johnny H. Evers; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The ease with which flying insects, birds and bats negotiate confined, obstacle-cluttered airspace has long inspired us with visions of human-designed aerial machines with similar performance. Flying animals exhibit capabilities for aerial acrobatics, insensitivity to wind gusts, avoiding collision with or intercepting fixed and moving objects, landing and take off from small perches, and numerous other feats of flight agility that are beyond those of human-engineered vehicles. Although we are ... |
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| Single Sensor Scheduling for Multi-Site Surveillance (PREPRINT) |
NOV 2007 |
26 pages |
| Authors:
David E. Jeffcoat; Mesut Yavuz; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| This paper is concerned with scheduling a single sensor to visit a number of sites with possibly time-variant dynamics. The paper motivates and presents a mathematical model for a sensor scheduling problem arising in the context of military operations research. The contributions made in the paper include the development and comparison of both deterministic and stochastic sensor scheduling methods. Results obtained in the paper show that the proposed heuristic methods ... |
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| Experimental Elastic Deformation Characterization of a Flapping-Wing MAV Using Visual Image Correlation |
NOV 2007 |
18 pages |
| Authors:
Kelly Stewart; Roberto Albertani; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| This presentation will detail AFRL/RW's collaboration with the University of Florida to derive a method for estimating elastic deformation in flexible, flapping wings. By knowing the elastic deformation that occurs, researchers can better understand the mechanics and aerodynamic effects behind flexible, flapping wings and apply that knowledge to various design aspects of micro air vehicles (MAV's) such as wing structure, guidance and control, etc. |
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| Multiscale Modeling of Particle-Solidification Front Dynamics, Part 3: Theoretical Aspects and Parametric Study (Preprint) |
SEP 2007 |
27 pages |
| Authors:
Justin W. Garvin; Yi Yang; H. S. Udaykumar; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The development of the solidified microstructure in metal-matrix composites depends on complex interactions between non-planar solidification fronts and multiple particles. The problem is multiscale in nature; the motion of the particle (under the action of a nano-scale disjoining pressure force and a micro-scale viscous drag force) is dynamically coupled with the developing solidification front morphology, which is dependent on a variety of thermal conditions. Using computational techniques discussed in parts ... |
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| A C++ Architecture for Unmanned Aerial Vehicle Simulations |
SEP 2007 |
32 pages |
| Authors:
Peter H. Zipfel; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The C++ computer language is well suited to model multi-vehicle engagements. Its prowess is exemplified by the conversion of a unmanned aerial vehicle simulation from FORTRAN to C++. The new architecture accommodates besides UAVs and moving targets also targeting satellites. Its class structure is outlined, and the communication bus between the encapsulated vehicle-objects is discussed. A generic UAV model with five degrees-of-freedom fidelity is used to demonstrate the interactive features ... |
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| Design of the Air Force Research Laboratory Micro Aerial Vehicle Research Configuration |
AUG 2007 |
14 pages |
| Authors:
Kelly Stewart; Jeffrey Wagener; Gregg Abate; Max Salichon; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| The Air Force Research Laboratory Munitions Directorate (AFRL/MN) is presently involved in many aspects of micro aerial vehicle (MAV) research. Among these are: advanced modeling and simulation models for MAVs, aero-structural interaction, advanced guidance techniques, hardware-in-the-loop simulations, and vehicle integration. In order to optimize collaboration within AFRL and also with outside research organizations, it was decided that a common MAV configuration be designed that would serve as a reference for ... |
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| High Strain Rate Properties of Tantalum Processed by Equal Channel Angular Pressing |
AUG 2007 |
18 pages |
| Authors:
Philip J. Flater; Joel W. House; James M. O'Brien; William F. Hosford; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Current ingot refinement and solidification techniques used in tantalum processing often result in inconsistent mechanical properties. Subsequent processing by equal channel angular pressing (ECAP) has been shown to reduce or eliminate internal structural variations as well as part-to-part variability [2]. This paper presents the effects of ECAP processing on the properties of tantalum. The materials of interest are 2.5-inch round bar tantalum supplied by H.C. Starck and Cabot Supermetals. Three ... |
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| High Strain Rate Mechanical Properties of Epoxy and Epoxy-Based Particulate Composites |
AUG 2007 |
35 pages |
| Authors:
Jennifer L. Jordan; D. W. Richards; Brad White; Naresh N. Thadhani; Jonathan E. Spowart; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| Polymers and polymer-based particulate composites are becoming increasingly used in aerospace structural applications, where they experience complex, non-static loads. Correspondingly, the high strain rate mechanical properties are of increasing importance. This paper investigates the properties of epoxy - bisphenol-A/diethanolamine epoxy (Epon 826/DEA) - and epoxy-based particulate composites across strain rates from 10(-3) to 10(5) /s. The samples were tested using Instron, traditional split Hopkinson pressure bars (SHPBs) and a miniaturized ... |
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| Detonation Shock Radius Experiments (Briefing Charts) |
AUG 2007 |
20 pages |
| Authors:
David E. Lambert; Joshua Debes; D. S. Stewart; Sunhee Yoo; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Simulating the Dynamics of Particles Interacting with Solidification Fronts (Preprint - Briefing Charts) |
JUL 2007 |
48 pages |
| Authors:
Justin Garvin; Yi Yang; H. S. Udaykumar; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| 1) Developed a multiscale numerical approach to solve particle-solidification front problems in a general manner. 2) Model can be generalized to solve a variety of problems involving interacting interfaces. 3) First to look at the physics from a nonlinear dynamics point-of-view (i.e. phase-space point of view). 4) Model captures essential physics that past research has neglected. |
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| Compressive Properties of Extruded Polytetrafluoroethylene |
JUL 2007 |
14 pages |
| Authors:
Jennifer L. Jordan; Jason R. Foley; Clive R. Siviour; Eric N. Brown; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Polymers are becoming increasingly used in aerospace structural applications, where they experience complex, non-static loads. Correspondingly, the mechanical properties at high strain rates are of increasing importance in these applications. This paper presents an investigation of the properties of Dupont 9B polytetrafluoroethylene (PTFE) across strain rates from 10-3 to 10 5 s-1 (see paper). The samples were tested using an Instron mechanical testing machine for static loading, traditional split Hopkinson ... |
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| Equation of State of Aluminum-Iron Oxide-Epoxy Composite |
JUL 2007 |
11 pages |
| Authors:
Jennifer L. Jordan; Jason R. Foley; Richard D. Dick; Louis Ferranti; Naresh N. Thadhani; David L. McDowell; Ryan A. Austin; David J. Benson; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| We report on the measurements of the shock equation of state (Hugoniot) of an Al/Fe2O3/epoxy composite, prepared by epoxy cast curing of powder mixtures. Explosive loading, with Baratol, trinitrotoluene (TNT), and Octol, was used for performing experiments at higher pressures, in which case shock velocities were measured in the samples and aluminum, copper, or polymethyl methacrylate (PMMA) donor material, using piezoelectric pins. The explosive loading of the metal donors (aluminum ... |
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| Response Surface Mapping Technique Aids Warfighters |
MAY 2007 |
5 pages |
| Authors:
Bruce C. Patterson; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Scientists apply innovative data mining and visualization techniques to real-world weapon penetration mechanics problems. |
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| High Strain Rate Mechanical Properties of Epoxy and Epoxy-Based Particulate Composites (Preprint) |
MAY 2007 |
13 pages |
| Authors:
Jennifer L. Jordan; Wayne Richards; Brad White; Jonathan E. Spowart; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| Polymers and polymer-based particulate composites are becoming increasingly used in aerospace structural applications, where they experience complex, non-static loads. Correspondingly, the high strain rate mechanical properties are of increasing importance. This paper investigates the properties of epoxy - bisphenol-A/diethanolamine epoxy (Epon 826/DEA) - and epoxy-based particulate composites across strain rates from 10(exp -3) to 10(exp 5) /s. The samples were tested using Instron, traditional split Hopkinson pressure bars (SHPBs) and ... |
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| An Investigation of a Dynamic Sensor Motion Strategy |
DEC 2006 |
15 pages |
| Authors:
Nathan P. Yerrick; David E. Jeffcoat; Abhishek Tiwari; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| This paper considers a dynamic sensor coverage problem in which a single mobile sensor attempts to monitor multiple sites. Sensor motion is modeled using a discrete time, discrete state Markov process. State dynamics at each site are modeled as a linear system. A stochastic simulation is used to demonstrate previously derived theoretical conditions under which a single sensor is or is not sufficient to maintain a bounded estimate of the ... |
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| A Hydrocarbon Fuel Flash Vaporization System for a Pulsed Detonation Engine |
DEC 2006 |
29 pages |
| Authors:
K. C. Tucker; Paul I. King; Frederick R. Schauer; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Practical operation of pulsed detonation propulsion requires operation on kerosene-based jet fuels. These low vapor pressure fuels remain in liquid form at typical pulsed detonation inlet conditions and residence times, and the subsequent presence of fuel droplets significantly hinders performance. A fuel flash vaporization system (FVS) was designed and built to reduce evaporation time and provide gaseous fuel to the PDE. Four fuels that vary in volatility and octane number ... |
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| Elastic-Viscoplastic an Isotropic Modeling of Textured Metals and Validation using the Taylor Cylinder Impact Text |
21 NOV 2006 |
23 pages |
| Authors:
B. Plunkett; O. Cazacu; R. A. Lebensohn; F. Barlat; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| An elastic-viscoplastic model for describing the anisotropic high-strain rate behavior of both low-symmetry and high symmetry textured materials is proposed. Yielding is described using a recently developed criterion which can capture simultaneously anisotropy and compression-tension asymmetry associated with deformation twinning. The anisotropy coefficients as well as the size of the elastic domain are considered to be functions of the accumulated plastic strain. The specific expressions for the evolution laws are ... |
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| Experimental Validation of Detonation Shock Dynamics in Condensed Explosives |
OCT 2006 |
29 pages |
| Authors:
David Lambert; D. S. Stewart; Sunhee Yoo; Bradley Wescott; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Experiments in the HMX-based condensed explosive PBX-9501 were carried out to validate a reduced, asymptotically derived description of detonation shock dynamics (DSD) where it is assumed that the normal detonation shock speed is determined by the total shock curvature. The Passover experiment has a lead disk embedded in a right circular cylindrical charge of PBX-9501 and is initiated from the bottom. The subsequent detonation shock experiences a range of dynamic ... |
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| Measured Airblast Environment From an Explosive Charge Having a Scored Metal Casing |
OCT 2006 |
17 pages |
| Authors:
Alan P. Ohrt; Seung J. Lee; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| For most applications, the introduction of a metallic casing tends to reduce the intensity of the airblast from the cased charge. Most predictive methods assume that the inertial resistance of the casing is the dominant parameter in estimating the reductions in peak airblast pressure and impulse. This enables the use of simple formulae to estimate bare charge equivalents for cased charges which consider only the relative masses of explosive and ... |
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| A Validation of First-Order Detonation Shock Dynamics Theory |
OCT 2006 |
8 pages |
| Authors:
David Lambert; Sunhee Yoo; D. S. Stewart; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| High energy explosives are used in a variety of applications, from military to industrial processes. The use of embedded, inert material "wave shapers" is a primary method to customize the detonation front for desired ex-plosive applications. These systems create detonation states that do not follow the simple line of sight, or Huy-gens model and, hence, advanced detonation physics with associated theory are required. The theory of detonation shock dynamics (DSD) ... |
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| Adaptable Miniature Initiation System Technology (AMIST) |
SEP 2006 |
5 pages |
| Authors:
Kenneth Bradley; Chris Martin; Ed Wild; Roger Platteborze; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| The ever-changing nature of warfare presents constant challenges to weapon system designers, who must carefully consider various perspectives of mutual importance. Specifically, designers must address constraints associated with newly developed aircraft, such as the F-22 andF-35, which carry their stores internally and thus have size limitations on their payloads. Weapons designers must also recognize the weight of political pressures that fuel concerns about a given weapon's potential to cause collateral ... |
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| A Study of Composite Strengthening Through Application of an Electric Field (PREPRINT) |
SEP 2006 |
12 pages |
| Authors:
Robert L. Sierakowski; Igor Y. Telichev; Olesya I. Zhupanska; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| This paper studies effects of an electric field on the mechanical response of unidirectional carbon fiber polymer matrix composites. The existing experimental evidence suggests that exposure of a composite material to the electromagnetic field leads to changes in the material's strength and resistance to delamination. We have analyzed the effects promoting this phenomenon: coupling of mechanical and electromagnetic fields and Joule heat effects and develop an experimental setup for impact ... |
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| Reflective and Polarimetric Characteristics of Urban Materials |
SEP 2006 |
12 pages |
| Authors:
Douglas G. Jones; Dennis H. Goldstein; Jonathan C. Spaulding; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| A spectropolarimetric reflectometer is used to measure the monostatic bidirectional reflectance distribution function (mBRDF) and the complete Mueller matrix of a number of urban type materials over a broad spectral region. Derivative features from these measurements are computed and stochastic models of each material are constructed. The models are then used to generate data for separability studies by implementation of a kernel-based linear discriminant classification technique. The purpose for this ... |
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| A Study of Impact Response of Electrified Organic Matrix Composites (Preprint) |
SEP 2006 |
21 pages |
| Authors:
Robert L. Sierakowski; Igor Y. Telichev; Olesya I. Zhupanska; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| The existing experimental evidence suggests that organic matrix composites sustain less impact damage when an electric field is applied. The intricate interaction of an electrical field and mechanical load is governed by coupling of the mechanical and electromagnetic fields via the Lorentz force as well as by the processes undergoing at the microscopic level: Joule heat, fiber-matrix interface changes, etc. The current work includes both experimental and theoretical investigations of ... |
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| The Wireless Network Jamming Problem (Preprint) |
SEP 2006 |
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| Authors:
Clayton W. Commander; Panos M. Pardalos; Valeriy Ryabchenko; Stanislav Uryasev; Grigoriy Zrazhevsky; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| In adversarial environments, disabling the communication capabilities of the enemy is a high priority. We introduce the problem of determining the optimal number and locations for a set of jamming devices in order to neutralize a wireless communication network. This problem is known as the WIRELESS NETWORK JAMMING PROBLEM. We develop several mathematical programming formulations based on covering the communication nodes and limiting the connectivity index of the nodes. Two ... |
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| Design, Testing, and Safety Considerations of an Optically Isolated Firing Set |
SEP 2006 |
14 pages |
| Authors:
Mark W. Heyse; Keith A. Jamison; Ronald E. Stearns; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| Experimental investigations at the Air Force Research Laboratory's Munitions Directorate required a firing set to initiate detonators in ultra-high-voltage experiments, but commercial firing sets with adequate high voltage isolation could not be found. To resolve this issue a Directorate team designed, fabricated a new firing set, verified that it met all design requirements, and obtained safety board approval for its use. The patented design uses all plastic fiber optic cables, ... |
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| A Comparison of Trajectory Determination Approaches for Small UAVs |
SEP 2006 |
14 pages |
| Authors:
Johnny H. Evers; Murray B. Anderson; Juan L. Lopez; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| In considering the problem of small unmanned aerial vehicle (SUAV) surveillance mission in a target rich environment, it is desirable to follow a trajectory path that maximizes targets coverage and observation time, while minimizing airframe maneuvering. Motivated by this requirement, this paper investigates the merits of multiple vehicle trajectory path schemes. Genetic Algorithms (GAs) and local optimum techniques are compared to a more conventional defined-path approach. The authors also introduce ... |
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| A Comparison of Trajectory Determination Approaches for Small UAVs |
SEP 2006 |
14 pages |
| Authors:
Murray B. Anderson; Juan L. Lopez; Johnny H. Evers; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| In considering the problem of small unmanned aerial vehicle (SUAV) surveillance mission in a target rich environment, it is desirable to follow a trajectory path that maximizes targets coverage and observation time, while minimizing airframe maneuvering. Motivated by this requirement, this paper investigates the merits of multiple vehicle trajectory path schemes. Genetic Algorithms (GAs) and local optimum techniques are compared to a more conventional defined-path approach. The authors also introduce ... |
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| Hypersonic and Unsteady Flow Science Issues for Explosively Formed Penetrators |
AUG 2006 |
22 pages |
| Authors:
Kirk Vanden; Steve Ellison; James Wilson; Ben Case; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| The technology of hypersonic projectiles is becoming mature from a metal physics perspective but there are still unsolved challenges relating to flight characteristics and aero dynamic stability. These projectiles deform under explosive loads and accelerate to hypersonic speeds in 2x10-6 seconds. In addition, these projectiles operate at sea-level conditions, a high-speed flight regime not commonly studied. The objective of this effort is to study the aerodynamics characteristics of deformable projectiles ... |
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| Hypersonic and Unsteady Flow Science Issues for Explosively Formed Penetrator Warheads |
AUG 2006 |
10 pages |
| Authors:
Kirk Vanden; Steve Ellison; Ben Case; Jacobs Sverdrup; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| The technology of hypersonic projectiles is becoming mature from a metal physics perspective but there are still unsolved challenges relating to flight characteristics and aerodynamic stability. These projectiles deform under explosive loads and accelerate to hypersonic speeds in 2x10-6 seconds. In addition, these projectiles operate at sea-level conditions, a high-speed flight regime not commonly studied. The objective of this effort is to study the aerodynamics characteristics of deformable projectiles flying ... |
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| A Study of Composite Strengthening Through Application of an Electric Field |
JUL 2006 |
12 pages |
| Authors:
Robert L. Sierakowski; Igor Y. Telichev; Olesya I. Zhupanska; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
|
| This paper studies effects of an electric field on the mechanical response of unidirectional carbon fiber polymer matrix composites. The existing experimental evidence suggests that exposure of a composite material to the electromagnetic field leads to changes in the material's strength and resistance to delamination. We have analyzed the effects promoting this phenomenon: coupling of mechanical and electromagnetic fields and Joule heat effects and develop an experimental setup for impact ... |
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| Infrared Spectroscopy of Hydrogen Cyanide in Solid Parahydrogen (Briefing Charts) |
JUL 2006 |
20 pages |
| Authors:
C. M. Lindsay; Mario E. Fajardo; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| Solid parahydrogen features: 1)Weak intermolecular interactions; 2) Slow relaxation timescales; 3) Quantum crystal; self-annealing via tunneling; 4) Homogeneous environment; 5) Large intermolecular distance, 3.78 Parahydrogen as a matrix: 1) Very small matrix shifts, predictable (-0.5 %); 2) Nearly free rotation for small molecules; 3) High impurity mobility; 4) Narrow spectral linewidths ( |
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| Rotational Dynamics of Small Molecules in Quantum Solids and Liquids (Briefing Charts) |
JUL 2006 |
16 pages |
| Authors:
Mario E. Fajardo; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| High resolution Infrared (IR) absorption spectra of diatomic dopants in solid pH2 provide rigorous tests of theories describing molecular rotations in solids. Leading candidate theories cannot explain strong linear correlation. |
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| Elastic-Viscoplastic Anisotropic Modelling of Textured Metals and Validation Using the Taylor Cylinder Impact Test |
JUN 2006 |
41 pages |
| Authors:
B. Plunket; O. Cazacu; F. Barlat; R. A. Lebensohn; AIR FORCE RESEARCH LAB EGLIN AFB FL MUNITIONS DIRECTORATE
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| An elastic-viscoplastic model for describing the anisotropic high-strain rate behavior of both low-symmetry and high-symmetry textured materials is proposed. Yielding is described using a recently developed criterion which can capture simultaneously anisotropy and compression-tension asymmetry associated with deformation twinning. The anisotropy coefficients as well as the size of the elastic domain are considered to be fimctions of the accumulated plastic strain. The specific expressions for the evolution laws are determined ... |
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