| Attempts to Create Ball Lightning with Triggered Lightning |
Oct-2009 |
33 pages |
| Authors:
Jonathan D Hill; Martin A Uman; Michael Stapleton; Douglas M Jordan; Alexander M Chebaro; Christopher J Biagi; FLORIDA UNIV GAINESVILLE DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
 | During the 2008 ball lightning experiment, around 100 different material samples were exposed to both relatively continuous (initial stage and inter-stroke continuing current) and to impulsive (return stroke) triggered lightning current. All events with properties similar to those reported by eye-witness and laboratory accounts of ball lightning were produced by slowly varying, relatively low amplitude currents during the initial stage of the triggered-lightning process. No events with sustained luminosity duration ... |
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| Mitigation Systems for Confined Blast Loading - Crew Protection in Armored Vehicles |
Apr-2009 |
151 pages |
| Authors:
Katherine M Gaulke; MARYLAND UNIV COLLEGE PARK
|
| Confined blast behavior and blast mitigation structures for the protection of occupants within a confined space subjected to high explosive blast, were examined through numerical analysis and laboratory testing. The mitigating structure's weight and geometry were of particular interest since performance was targeted for inclusion within the limited interior space of an armored vehicle. Numerical analysis using eta/VPG modeling software and LS DYNA dynamic analysis software examined the effects of ... |
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| Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection |
Feb-2009 |
17 pages |
| Authors:
Zafar Iqbal; NEW JERSEY INST OF TECH NEWARK
|
| SUMMARY: Three types of nanotechnology-based passive and smart barrier coatings for corrosion protection discussed (1) Plasma-deposited conducting carbon polymer PPN can be used to protect small device or engine components and has been demonstrated to protect PEM fuel cell current collecting bipolar metal plates; (2) Carbon nanotube pints/links can form smart protective coatings via p-n junction layers which can electrically sense coating damage due to corrosion (3) semiconducting, thermochromic polydiacetylene ... |
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| Advancements in Steel for Weight Reduction of P900 Armor Plate |
Dec-2008 |
8 pages |
| Authors:
R A Howell; J S Van Montgomery; D C Aken; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD SURVIVABILITY MATERIALS BRANCH
|
| Ballistic tests were conducted on a high manganese and high aluminum austenitic steel that is age hardenable. These lightweight steels (12 to 18% lower in density) were investigated as alternatives to MIL-PRF- 32269 steel alloys for application in P900 perforated armor currently used for Army ground combat systems. Two steel plates with nominal composition in weight percent of Fe-30Mn-9Al-1Si-0.9C-0.5Mo were evaluated for V50 against 0.30 caliber armor piercing and 0.50 ... |
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| Crack Detection in Armor Plates Using Ultrasonic Techniques (PREPRINT) |
01 MAR 2007 |
7 pages |
| Authors:
Thomas J. Meitzler; Gregory Smith; Michelle Charbeneau; Euijung Sohn; Mary Bienkowski; Ivan Wong; Allen H. Meitzler; ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND WARREN MI
|
| A method of using piezoelectric lead zirconate titanate (PZT) transducers to characterize the vibrational modes of Vehicle Body Armor Support System (VBASS) plates and its preliminary results are presented. The amplitude of the vibrational modes of undamaged plates are compared to the vibrational mode amplitudes of damaged plates and shown to be clearly different. Plates for testing are damaged either by a blunt impact to the ceramic plate surface or ... |
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| Polarimetric Thermal Imaging |
MAR 2007 |
121 pages |
| Authors:
Fook L. Loo; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Passive infrared (IR) imagers, using intensity contrast for target detection, are often limited by low target-background contrast. Detecting stationary targets against cluttered backgrounds presents an even bigger challenge. Polarized signatures can be used as an additional discriminator, to improve target detection probability and reduce false alarm rate. In this research,a polarimetric thermal imager, operating in the mid wave infrared (3-5 m), was set up using the Merlin InSb camera with ... |
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| Evaluation of Factors Contributing to Damping of Coated and Uncoated Titanium Plates |
23 MAR 2006 |
260 pages |
| Authors:
Dustin W. Lee; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| High Cycle Fatigue (HCF) is the leading cause of component failure in gas turbine engines today, which poses great risk to aircraft, engines, and their crews. Mitigation of HCF effects has become a priority topic, and the damping benefits of hard coatings are being reevaluated for this purpose. Research was conducted to further understanding of damping measurements on these coatings. This study continues work to characterize the damping effects of ... |
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| Software for the Design and Certification of Unitized Airframe Components |
23 FEB 2006 |
33 pages |
| Authors:
Richardo Actis; ENGINEERING SOFTWARE RESEARCH AND DEVELOPMENT INC(ERSD) ST LOUIS MO
|
| This report presents the results of the investigation of two important subjects associated with the design and certification in unitized airframe components. The first subject is related to the effects of residual stresses on the structural stability of thin unitized components machined from aluminum plates, in particular 7050-T74 and 7050-T7451 plates. The findings indicate that residual stresses introduced in a plate during the rolling operation (bulk stresses) and residual stresses ... |
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| Characterization of Deformation and Failure of Stainless Steel Welds |
17 FEB 2006 |
11 pages |
| Authors:
Rodney J. Clifton; BROWN UNIV PROVIDENCE RI DIV OF ENGINEERING
|
| Kolsky bar experiments have been used to determine the high-strain-rate response of AL6XN welds - including the base material, the heat-affected zone, and the weld. A finite element model for analyzing ductile fracture near the weld as been developed and implemented as a material routine VUMAT in ABAQUS/Explicit. The FE model involves a Gurson-type constitutive description for porous materials, combined with a microstructural length scale and an upper pound approach ... |
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| Electronically Reconfigurable Microwave Lens Antennas |
13 DEC 2005 |
54 pages |
| Authors:
Liang Xue; Vincent Fusco; QUEEN'S UNIV BELFAST (NORTHERN IRELAND)
|
| The purpose of this report is to present the results of further investigations into the operation and design of two-dimensional Luneburg Lenses at 24 GHz, with the possibility for electronic control of their behavior. Various lens design techniques are illustrated; these include a holey dielectric lens (drilled dielectric), and a holey plate lens (etched holes on the upper metal plate). Ray tracing theory is presented which shows the general properties ... |
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| Experimental and Numerical Analysis of Transpiration Cooling of a Rocket Engine Using Lamilloy (Trademark) Plates (POSTPRINT) |
DEC 2005 |
13 pages |
| Authors:
T. P. Auyeung; R. Cohn; E. Coy; S. A. Danczyk; C. Papesh; P. Sweeney; NORTHROP GRUMMAN SPACE AND MISSILE SYSTEMS CORP REDONDO BEACH CA SPACE TECHNOLOGY
|
| Transpiration cooling of rocket engine thrust chamber walls has the potential for improving the performance of liquid rocket engines by reducing the required cooling flow. For the TR107 hydrocarbon booster engine, it is estimated that replacing the proposed chamber wall film cooling with transpiration cooling could result in an engine Isp increase of 2% to 3%, which provides the potential to increase the maximum booster delivery capability by 4000-5000 lbm. ... |
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| Investigation of Transient Forces Produced by Gases Expelled from Rapidly Heated Surfaces |
13 JUL 2005 |
7 pages |
| Authors:
B. C. Souza; A. D. Ketsdever; E. P. Muntz; UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF AEROSPACE AND MECHANICAL ENGINEERING
|
| A torsional impulse balance has been developed as a new diagnostic tool to study fundamental processes in laser-surface interactions. The impulse balance has been designed and tested with a robust calibration system to measure impulsive forces with resolution as low as 1 nano-Newton-second. A simple technique has been developed to accurately determine the force as a function of time from the motion of the nano-impulse balance system (NIBS). This technique ... |
|
| Self-Activated Micro Direct-Methanol Fuel Cell (muDMFC) at Near Room Temperature |
15 JUN 2005 |
53 pages |
| Authors:
|
| This research project was focused on the development and testing of Micro Direct-Methanol Fuel Cells (Micro DMFC). A Si-based Micro DMFC was developed and its electrochemical characteristics studied. The peak power density reached 50 mW/sq cm at 60 deg C. A new MEA design was successfully developed to mitigate MeOH crossover without requiring novel membranes. A Micro DMFC was also fabricated by using photochemically etched stainless steel bipolar plates and ... |
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| Virtual Experiments to Determine Behind-Armor Debris for Survivability Analysis |
DEC 2004 |
7 pages |
| Authors:
Anand Prakash; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD SURVIVABILITY LETHALITY ANALYSIS DIRECTORATE
|
| When a projectile perforates the armor of a vehicle, the residual projectile entering the vehicle is accompanied by a much wider cloud of behind- armor debris (BAD) generated by stress wave interactions. BAD plays an important role in the evaluation of survivability of crew and components in a vehicle under fire. Survivability and vulnerability analysis codes (e.g., MUVES) require an input of BAD characteristics of the armor for each threat ... |
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| Numerical Simulation of Adiabatic Shear Bands in Ti-6Al-4V Alloy Due to Fragment Impact |
DEC 2004 |
3 pages |
| Authors:
Muege Fermen-Coker; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Current distributions of continuum mechanics codes used by the Army do not have the capability to model failure associated with plastic shear localizations in ballistic applications, such as plugging failure of targets due to ballistic impact by blunt-nosed projectiles. This paper discusses the development and validation of a computational capability to accurately model highly localized deformations in complex projectile-target interactions germane to survivability and lethality technologies for the Army's Future ... |
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| Fatigue Crack Growth in Several 7050T7451 Aluminium Alloy Thick Section Plates with Aircraft Manufacturer's and Laboratory Surface Finishes Representing Some Regions of the F/A-18 Structure |
DEC 2003 |
|
| Authors:
Simon A. Barter; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION VICTORIA (AUSTRALIA) AIR VEHICLES DIV
|
 | This is the third in a series of papers that examine material factors likely to influence the fatigue life of F/A-18 structures. Work leading up to these papers has highlighted a number of concerns about the fatigue variability of the 7050 aluminium alloy thick section plate and the effect that the surface condition of finished components has on service fatigue crack initiation and life. This report examines a series of ... |
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| PA116/171 Containers ona Wood Pallet With Metal Top Adapter, MIL-STD- 1660, First Article Tests |
SEP 2003 |
26 pages |
| Authors:
Jeffery L. Dugan; ARMY DEFENSE AMMUNITION CENTER MCALESTER OK VALIDATION ENGINEERING DIV
|
| The U.S. Army Defense Ammunition Center (DAC), Validation Engineering Division (SJMAC-DEV) conducted First Article Tests per MIL-STD-1660, "Design Criteria for Ammunition Unit Loads" on the PA116/171 containers on a wood pallet with metal top adapter provided by Alliant Tech Ordnance and Ground Systems LLC of Plymouth, MN. Two separate containers were tested with total weights of 2,470 lbs each. The tests accomplished on the test units were the stacking, repetitive ... |
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| Penetration of a Highly Oblique Steel Plate by a Thin Disk |
SEP 2002 |
28 pages |
| Authors:
Nathaniel Bruchey; Kent Kimsey; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| Segmented rod penetrator concepts created interest in the ballistic performance of high-density, low length-to-diameter (LID) ratio penetrators, but there was a lack of data showing the performance of such thin disks vs. high- obliquity targets. An experimental and computational study was conducted to examine the basic case of a single tungsten heavy alloy disk with an LID of 1/8 impacting a high-obliquity (65 degrees) rolled homogeneous armor steel plate at ... |
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| Evaluation of Residual Stresses and Their Influence on Distortion in the Decoiling and Welding Processes |
AUG 2002 |
34 pages |
| Authors:
Wojciech Z. Misiolek; Pawel Kazanowski; LEHIGH UNIV BETHLEHEM PA INST FOR METAL FORMING
|
| An analysis of de-coiling process is provided. The expression for equilibrium of internal stresses within de-coiled plate during welding was established. First simulations of the de-coiling process have been prepared using Finite Element Modeling technique. Experimental verification of numerical results has been performed. The experimental results are in very good agreement with the numerical results. More insight into the changes of the sample material during deformation was achieved by careful ... |
|
| iMAST Quarterly, Number 2, 2002 |
Jan-2002 |
9 pages |
| Authors:
APPLIED RESEARCH LABORATORY STATE COLLEGE PA
|
| Rhenium, as a pure refractory metal, is a very attractive material for high temperature structural and energy system applications such as solar-powered rocket engines, heat exchangers, and space and missile propulsion systems. Rhenium has many advantages over other candidate materials including tungsten. It offers excellent erosion resistance for components in high temperature rocket engines and hot gas valves. Rhenium has the second highest melting temperature next to tungsten. Unlike tungsten, ... |
|
| Electromagnetic Code Consortium Benchmarks |
DEC 2001 |
18 pages |
| Authors:
Andrew Greenwood; AIR FORCE RESEARCH LAB KIRTLAND AFB NMDIRECTED ENERGY DIRECTORATE
|
| Several additions to the metallic Electromagnetic Code Consortium (EMCC) benchmarks are described. The new geometries include a cube, a prism, a pyramid and a trihedron. These geometries include edge, corner, and multipath scattering effects. In addition, the first EMCC antenna benchmark composed of an array of elements on a finite metal plate is described. Measured and computed scattering or radiation data for each new geometry is shown. Computed data is ... |
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| Modeling and Lowering Residual Stresses in Bonded Composite Patch Repairs of Metallic Aircraft Stuctures |
01 AUG 2001 |
8 pages |
| Authors:
C. T. Sun; M. Caruthersw; PURDUE UNIV LAFAYETTE IN
|
| The technology in using composite patches to repair cracked aging aircraft structures has been proven to be efficient and economical. One of the problems resulting from bonding of a composite patch to the metallic host structure is thermal stresses induced from bonding the patch to the host structure at elevated temperatures. The main objective of this research was to develop multi-step curing procedures in order to reduce the level of ... |
|
| Sea Surface Micro-Structure: Relation to Air-Sea Fluxes, Bubble Transport and Electromagnetic Wave Radiation |
AUG 2001 |
2 pages |
| Authors:
Charles Cox; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
|
| Emphasis in the period since April has been on observations and analysis of thermal structures associated with microturbulence and air/sea thermal processes at the sea surface. our method of observation is based on an imaging infrared camera that we have adapted to use from a small boat. The camera responds to radiation in the three to five micrometer wavelength range. This is a useful range because the intensity of black ... |
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| Impact and High Strain Rate Response of 3-D Woven Systems |
17 FEB 2001 |
71 pages |
| Authors:
J. N. Singletary; R. lA. Coffelt; J. W. Gillespie Jr.; B. A. Gama; 3TEX ENGINEERED FIBER PRODUCTS CARY NC
|
| 3-D and 2-D woven systems were characterized both statically and dynamically to assess the relative advantages of 3-D weaves in armor and impact resistant systems. Five different 3WeaveTM 3-D orthogonal fabrics were woven from S-2 glass rovings, including both flat goods and near-net-shape preforms. 3WeaveTM and a baseline, 2-D woven fabric were consolidated via vacuum assisted resin transfer molding using rubber toughened epoxy vinyl ester and rubber- toughened epoxy. Static ... |
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| Acoustic Emission Detection Using Fiber Bragg Gratings |
2001 |
8 pages |
| Authors:
Ignacio Perez; Hong-Liang Cui; Eric Udd; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
|
| A systematic study of acoustic emission detection using fiber Bragg grating sensors is presented. In this, we attempt to use the fiber Bragg grating to sense the dynamic strain created by a passing ultrasonic wave signal. Our goal is to see if such a sensor is possible, and if so, what the detection sensitivity and limitations will be. To answer these questions. we carried out several experiments involving the detection ... |
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| A Computational Study of Munitions Response to Double Impact and Crushing Impact From a Flyer Plate |
AUG 2000 |
137 pages |
| Authors:
Patsy B. Simmers; Richard E. Lottero; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| This report describes the results of a series of hydrocode computations, each of which modeled a steel flyer plate striking a single munition, either an M2A3 or an M483, in one of two different mounting configurations. One mounting configuration was for the munition to be first struck by the flyer plate and then to subsequently translate and strike a backing plate. The second ... |
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| Dynamic Constitutive and Failure Characterization of Rate Sensitive Alloys |
20 JUN 2000 |
8 pages |
| Authors:
Ares J. Rosakis; G. Ravichandran; CALIFORNIA INST OF TECH PASADENA OFFICE OF SPONSORED RESEARCH
|
| The objectives of this research program are (1) to establish critical conditions for initiation and growth of adiabatic shear bands in pre-notched plates subjected to asymmetric impact loading and (2) investigate the transition between competing failure modes under varying loading conditions. Typically, failure under asymmetric loading may occur by either dynamic cracking or adiabatic shear banding, both of which may be observed in the same specimen or ... |
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| RRA Heat Treatment of Large Al 7075-T6 Components |
APR 2000 |
11 pages |
| Authors:
R. T. Holt; Raizenne Wallace; W. Wallace; D. L. DuQuesnay; NATIONAL RESEARCH COUNCIL OF CANADA OTTAWA (ONTARIO) INST FOR AEROSPACE RESEARCH
|
| Retrogression and re-aging (RRA) is a heat treatment process performed on the aluminum alloy 7075 in the T6xxx temper condition to improve its resistance to corrosion, while at the same time maintaining the high strength levels required for aircraft structural applications. For large extruded or forged parts, we have determined that the most practical process involves retrogression at 195 degrees centigrade for 40 minutes, followed by rapid cooling and full ... |
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| A Shear Banding Model for Penetration Calculations |
APR 2000 |
67 pages |
| Authors:
Martin N. Raftenberg; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A model for introducing the effects of adiabatic shear banding into a penetration calculation was installed into the EPIC wavecode. These effects are deemed to be reduction in the ratio of flow stress to the value predicted by the Johnson-Cook strength model and increase in spall pressure. A strain-rate- and temperature-dependent instability strain is determined from small-amplitude perturbation of constant-strain-rate simple shear. Imposed alterations in flow ... |
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| Surface Current Determination from Localized Measurements |
29 FEB 2000 |
134 pages |
| Authors:
Morris P. Kesler; Jim Maloney; Paul Harms; Stephen Blalock; Eric Kuster; GEORGIA TECH RESEARCH INST ATLANTA
|
| This report describes the results of a research program aimed at developing and demonstrating a technique for determining surface currents from a series of electromagnetic field measurements. Two back-propagation techniques were developed and validated through numerical simulations and measurements on laboratory-scale, conducting objects. The first technique is a planar spectral decomposition approach that utilizes magnetic field measurements on a plane in front of the body, ... |
|
| Copper Crusher Gauge Holder |
23 NOV 1999 |
6 pages |
| Authors:
Eugene W. Bowie; Raymond E. Bowen; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A copper crusher gauge holder for testing internal pressures of cartridges during test firing is provided. The copper crusher gauge holder has a circular aluminum upper plate and a circular aluminum lower plate having a layer of urethane rubber approximately 3/4 inch thick sandwiched between the plates. The gauge holder is bored to hold copper crusher gauges and center-bored to fit over a cartridge centerline primer tube. A series of ... |
|
| Thermomechanical Behavior of Functionally Graded Materials |
AUG 1998 |
87 pages |
| Authors:
J. N. Reddy; TEXAS A AND M UNIV COLLEGE STATION DEPT OF MECHANICAL ENGINEERING
|
| The research involved developing theoretical formulations and finite element analyses of the thermomechanical, transient response of functionally graded cylinders and plates. Nonlinearities (geometric and material), thermomechanical coupling (between elastic deformation and heat transfer), and power-law distribution of the two-constitutent material variation through the thickness were accounted for in the formulations. The first-order shear deformation plate theory is used for the kinematics of the plate problem. Numerical results of the deflections, ... |
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| A Numerical Study of Heat Transfer Behavior in Welding |
JUN 1998 |
|
| Authors:
Yasar V. Isiklar; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| A numerical model has been developed for three-dimensional transient conduction based temperature calculations in underwater wet welding on a thick rectangular plate. The numerical scheme is based on a fully implicit finite volume method. A variable mesh size centered around the moving heat source, and temperature dependent thermal properties have been used in the calculations. Convective, radiative and boiling surface thermal conditions have also been ... |
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| Aluminum Alloy Forgings Property/Performance Attributes; Focus: Fatigue and Durability Service Capabilities (les Pieces forgees en alliage d'aluminium les attributs de performance/caracteristiques themes: fatigue et durabilite capacites en service) |
MAY 1998 |
|
| Authors:
ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRANCE)
|
| Historically, many aluminum aircraft components have been made from forgings. However, to reduce airframe manufacturing cost aircraft manufacturers are converting to parts machined from thick plate. The results of recent research indicates that forgings often offer significant advantages over components machined from plate. The purpose of this report is to present this information. |
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| Detection of Corrosion Under Paint Using Magneto-Optic Imaging |
19 FEB 1998 |
|
| Authors:
Gerald Fitzpatrick; Richard Skaugset; PHYSICAL RESEARCH INC KIRKLAND WA
|
| This report describes developments in magneto-Optic imaging that make possible practical real-time imaging of surface corrosion under protective coatings in both steel and aluminum. The technology can also be applied to the detection of cracks. To accomplish imaging in steel a new method for producing rotating in-plane magnetization in steel parts was developed and combined with real-time magneto-optic imaging. Imaging in aluminum is accomplished by using an eddy-current excitation device ... |
|
| LIGA-Based Tunable Optical Filters for Multispectral IR Imagers and Gas Analyzers |
30 NOV 97 |
35 pages |
| Authors:
Thomas Ohnstein; HONEYWELL TECHNOLOGY CENTER PLYMOUTH MN
|
| The Honeywell Technology Center and the University of Wisconsin have developed microelectromechanical tunable IR filters for IR spectral analysis. The filters and integral actuators are fabricated by the MEMS LIGA process for making high-aspect-ratio metallic microstructures. The tunable IR filter is a mechanically deformable structure consisting of an array of parallel metal plates joined by spring flexures and driven by an integral linear actuator. The plates form an array of ... |
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| Determination of the Stress State From Transverse Wave Speeds in Isotropic Inelastic Solids |
AUG 97 |
26 pages |
| Authors:
Mike Scheidler; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| For a transverse acceleration wave propagating along a principal axis of strain in a nonlinear isotropic elastic solid, a simple formula due to Ericksen relates the wave speed to the stress and strain state at the wave front. We derive the appropriate generalization of this result for finite deformation viscoplasticity models based on the multiplicative decomposition of the deformation gradient into elastic and plastic parts. The inclusion of scalar internal ... |
|
| Magnetic Induction Launcher Models |
JUN 97 |
44 pages |
| Authors:
Paul R. Berning; Charles R. Hummer; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Various computer models developed to aid in the design of magnetic induction launchers or coilguns are described. The first models the launch process based on launcher circuit parameters, in particular, the coil inductance as a function of projectile position L(x). The second set of models calculates the overall inductance of the launcher coil both with and without the plate present The difference between the values deltaL = L(infinity)- L(O) has ... |
|
| Thickness Effects on a Cracked Aluminum Plate with Composite Patch Repair |
JUN 1997 |
252 pages |
| Authors:
Joel J. Schubbe; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
|
| Post-repair fatigue crack growth was investigated in 3.175, 4.826, and 6.35 mm thick aluminum panels asymmetrically repaired with boron/epoxy composite patches bonded to the plates with FM73 sheet adhesive. Patches were uniaxial with patch to panel stiffness ratios ranging from 0.46 to 1.3. Experimental fatigue tests were carried out at 120 MPa, R=0.1, and 10 Hz (sinusoidal) to measure patched and unpatched face crack lengths, center crack opening displacements, and ... |
|
| The National Shipbuilding Research Program. 1997 Ship Production Symposium, Paper Number 18: Development of a Production Optimization Program for Design and Manufacture of Light Weight/High Strength Hull |
APR 1997 |
10 pages |
| Authors:
Robert Latorre; Paul Herrington; NEW ORLEANS UNIV LA
|
| There is an interest in introducing a high speed marine vehicle for crew boat service to the offshore oil and gas fields in the Gulf of Mexico. Consequently, it is necessary to develop a light weight hull structure suitable for rapid modular construction. This paper presents the authors numerical and experimental evaluation of a lightweight aluminum hull panel. An optimization routine was developed to investigate the sensitivity of the design ... |
|
| Evaluation of the Friability Test (Evaluatie van de Friability Test) |
JAN 97 |
|
| Authors:
J. H. Scholtes; B. J. VAN DER Meer; PRINS MAURITS LABORATORIUM TNO RIJSWIJK (NETHERLANDS)
|
| In co-operation with SNPE, France, the friability test has been constructed. This test is applied to determine the effect of impact on an explosive substance which is a candidate to be assigned as an Extremely Insensitive Detonating Substance (EIDS). In this test a sample is directed against a steel plate with a velocity of about 150 m/s with the use of a gas gun. After having performed this test, the ... |
|
| Progress Report - Mechanical Properties Evaluation of ASTM A945 (HSLA- 65) Steels |
SEP 96 |
17 pages |
| Authors:
Eric M. Focht; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SURVIVABILITY STRUCTU RES AND MATERIALS DIRECTORATE
|
| This report documents the mechanical properties of steel plates for Navy use. These plates conform to American Society for Testing and Materials (ASTM) Standard A945, High-strength, Low-alloy (HSLA), Class 65. Plates of various thickness were purchased from two different producers to determine if the steel could be obtained on a production scale, as opposed to a custom order. Tensile and Charpy V-notch impact tests were performed on the steels, and ... |
|
| Buckling of Ship Grillages |
SEP 96 |
54 pages |
| Authors:
D. A. Danielson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The subject of this report is the mechanical behavior of stiffened plates, basic structural components of ships and submarines. The buckling loads of grillages subjected to axial compression with and without lateral pressure are calculated using a finite element based eigenvalue analysis. Insights are obtained into the ways in which the buckling loads and modes vary with various grillage dimensions. |
|
| Induction Heat Treatment - Phase I - Technology to Produce Monolithic Gradient Hardness Steel Armor |
SEP 96 |
75 pages |
| Authors:
Richard J. Squillacioti; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| This report details the results of Phase I of the Dual Hard Steel Armor Program funded by the PM, Survivability, U.S. Army Tank-Automotive Command (TACOM). This report investigates the use of an induction heat-treating process to produce a gradient hardness monolithic steel armor to complement MIL-A-46099, Armor Plate, Steel, Rolled-Bonded, Dual-Hardness, for thicknesses of approximately 0.5 in. Results of this investigation indicate that a conventionally heat-treated steel armor plate (tempered ... |
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| Effect of Bonded Insert Shape and Adhesive Thickness on Critical Stresses in a Loaded Plate |
AUG 96 |
|
| Authors:
R. L. Evans; M. Heller; DEFENCE SCIENCE AND TECHNOLOGY ORGANIZATION CANBERRA (AUSTRALIA)
|
| This report presents the results of finite element analyses conducted to calculate the magnitude of adhesive stresses for a large plate with a bonded insert, and study the interaction of key parameters including (1) insert shape, and (2) adhesive modulus and thickness, with maximum plate stresses. Results are presented for circular, oval and elliptical insert cases. It is shown that changing the key variables can improve the efficiency of such ... |
|
| Breeching Device. |
JUN 1996 |
|
| Authors:
Alexander G. Rozner; Bernard P. Howder; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A breaching device comprising a regular polygon structure in which identical, rectangular, Concave flying plate devices (shape charges) form the sides of the polygon, and a strong, rigid, lightweight structure holds the flying plate devices in position. The flying plate devices are identical and comprise a copper or copper alloy plate having a uniform thickness and a concave front face, a uniform elastomeric material layer attached to and covering the ... |
|
| Technical Support for Implementation of Aluminum Vapor Deposition Technology |
MAY 1996 |
|
| Authors:
Robert L. Hoye; Gene L. Fabian; INTERNATIONAL TECHNOLOGY CORP CINCINNATI OH
|
| Industrial production and maintenance activities conducted at Army depots typically include metal plating operations. For many years, cadmium has been commonly applied as a surface coating, using conventional electroplating processes, to provide a protective, corrosion-resistant finish. Cadmium is a toxic, carcinogenic metal and cadmium electroplating generates sludges, rinse waters, and spent plating solutions. Alternatives to cadmium electroplating exist. In many cases, aluminum coatings can be substituted for cadmium coating to ... |
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| Wavelet Domain Characterization & Localization of Modal Acoustic Emissions in Aircraft Aluminum |
APR 1996 |
12 pages |
| Authors:
Grant A. Gordon; Randy K. Young; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
|
| As machines age, broadband acoustic emission (AE) signals are emitted from unknown locations, often due to microscopic material degradation. Not only is the AE source location unknown, but the source mechanism and hence signal characteristics are also unknown. These signals then propagate along multiple, complex geometric paths, in various distorting modes experience mode conversion and wave guide selection, before finally reaching the sensors. In addition to this wave distortion, the ... |
|
| Fort Drum Ballistic Barrier Tests |
MAR 96 |
27 pages |
| Authors:
William S. De Rosset; Eleanor C. Deal; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Experiments were conducted to determine the response of a laminated target to small arms fire. The target represented tile ceiling used to separate tile floors of a two-story building in a live fire village at Fort Drum, New York. The target consisted of 3/4-in plywood, a steel plate, a second piece of 3/4-in plywood, a second steel plate, and a third piece of 3/4-in plywood. The tests were conducted to ... |
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| Electromagnetic Field Measurements Near a Single-Stage Reconnection Gun |
APR 95 |
35 pages |
| Authors:
William O. Coburn; Calvin Le; Harry Martin; ARMY RESEARCH LAB ADELPHI MD
|
| Electromagnetic (EM) field measurements were obtained near a single- stage reconnection gun accelerating a 194-gm, 4 x 4.5 x 1/4 in. aluminum plate. This type of EM launcher is of interest as an alternative for using explosive charges to launch a plate in the edge-on orientation. Electric and magnetic field measurements were designed to characterize the transient EM environment (EME) external to this capacitor-based EM launch system. The available data ... |
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METAL PLATES
