| Impact of Loading Distribution of Abrams Suspension on Track Performance and Durability |
03-Aug-2009 |
12 pages |
| Authors:
David Ostberg; Bill Bradford; TACOM RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI GROUND VEHICLE POWER AND MOBILITY
|
 | High life cycle costs coupled with durability and environmental challenges of tracked vehicles in South West Asia (SWA) have focused R&D activities on understanding failure modes of track components as well as understanding the system impacts on track durability. The durability limiters for M1 Abrams (M1, M1A1, and M1A2) T-158LL track systems are the elastomeric components. The focus of this study is to review test methodology utilized to collect preliminary ... |
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| Field Testing and Load Rating Report, Bridge S-1090 |
01-May-2008 |
103 pages |
| Authors:
Brett Commander; Jesse Grimson; Wilmel Varela-Ortiz; Terry R Stanton; Carmen Y Lugo; Gerald M Hansler; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| In June 2007, Bridge Diagnostics, Inc. (BDI), was contracted by the U.S. Army Corps of Engineers to perform live-load testing and load rating on Bridge S-1090 at Camp Casey, South Korea, in conjunction with two other structures, S-4360 and S-1801. The general goal of the live-load testing was to obtain and then utilize field measurements to verify an analytical model from which accurate load ratings could be obtained. A more ... |
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| Probing and Cavity Forming Equipment Investigation for Use in Melt Pour Explosive Loading Process. Prove-Out Study Using Controlled Cooling Equipment for Artillery Projectiles |
MAY 2008 |
22 pages |
| Authors:
Daniel Spicer; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ
|
| Prototype melt pour explosive loading equipment was procured and installed in support of load, assemble, and pack modernization program at various Army Ammunition Plants around the United States. This equipment uses a new and different approach to control the cooling process of melt poured munitions that is currently not used by facilities within the United States industrial base. The equipment purchased consists of a probing unit to control the cooling ... |
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| Clothe the Soldier Prototype K1 Load Carriage System Design Assessment using the APLCS Load Carriage Simulator |
01-Mar-2006 |
57 pages |
| Authors:
J M Stevenson; J T Bryant; J Doan; W A Rigby; S A Reid; QUEEN'S UNIV KINGSTON (ONTARIO)
|
| The objective of this study was to conduct a standardized assessment of the Clothe the Soldier (CTS) Prototype K1 pack on a computerized Load Carriage (LC) Simulator to assess the load control and load transfer capability of the CTS K1 Pack. These aspects of pack design were comprised of displacement, force, moment and pressure variables that had been validated on previously tested systems where LC Simulator outputs were compared to ... |
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| Assessment of the effect of No Stay, Bent Stay or Straight Stay when the Clothe the Soldier Rucksack is Worn with the Fragmentation Vest |
FEB 2006 |
32 pages |
| Authors:
S. A. Reid; J. M. Stevenson; I. Kudryk; QUEEN'S UNIV KINGSTON (ONTARIO)
|
| The Clothe the Soldier (CTS) load carriage system includes the Fragmentation Protection Vest (FPV) with Bullet Resistant Plates (BRP), Tactical Vest (TV), the Rucksack, and a Small Pack System which have been designed to be compatible Loads carried in the CTS rucksack often exceed the officially recommended 25 kg and are reported to approach 45 kg. Under these conditions, optimizing load distribution onto the torso becomes even more essential. The ... |
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| Ordered End-to-End Multicast for Distributed Multimedia Systems |
2006 |
11 pages |
| Authors:
H.-Peter Dommel; J. J. Garcia-Luna-Aceves; CALIFORNIA UNIV SANTA CRUZ DEPT OF COMPUTER ENGINEERING
|
| We address the problem of message ordering for reliable multicast communication. End-to-end multicast ordering is useful for ensuring the collective integrity and consistency of distributed operations. It is applicable for distributed multiparty collaboration or other multipoint applications, where the ordered reception of messages at all hosts is critical. Existing reliable multicast protocols largely lack support for ordering. Our novel mechanism can be added to existing reliable multicast services at low ... |
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| A Comparison of the Deformation, Flow, and Failure of Two Tungsten Heavy Alloys in Ballistic Impacts |
DEC 2005 |
|
| Authors:
Brian Schuster; Lee Magness; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
 | Ballistic tests were conducted with subscale long rod penetrators of two different processing conditions of the same tungsten heavy alloy. The liquid-phase sintered composite of 90% tungsten-9% nickel-01% cobalt (by weight) was tested in its low-strength, as -sintered and heat-treated condition, and in a high-strength, 50% cold-worked (by swaging) and aged condition. Consistent differences in the ballistic performance of the two lots of penetrators were observed, in depth of penetrations ... |
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| Development of a Dynamic Biomechanical Model for Load Carriage: Phase 4, Part C4: User's Manual for the Standardized Protocol of Mapping Skin Contact Pressure Using the Standardized Load Distribution Mannequin |
AUG 2005 |
42 pages |
| Authors:
L. J. Hadcock; QUEEN'S UNIV KINGSTON (ONTARIO) ERGONOMICS RESEARCH GROUP
|
| The Dynamic Biomechanical Model (DBM) requires input about pack geometry and the material property response of the load carriage suspension interface to resolve the forces acting on the body. Since there is extensive redundancy in applied forces (i.e., shoulder straps, load lifter straps, hip stabilizer straps and waist belt and skin contact pressure), it is not possible to describe the mechanical characteristics of pack components as combinations of linear and/or ... |
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| Characterization of Reinforced Concrete Bridges Using Dynamic Response Measurements for Use in Load Capacity Estimation |
APR 2005 |
43 pages |
| Authors:
Ziyad H. Duron; Daniel Sutoyo; Gene Lee; Yazmin Seda-Sanabria; ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS GEOTECHNICAL AND STRUCTURES LAB
|
| The U.S. Army Engineer Research and Development Center (ERDC) is leading research efforts for the development of rapid bridge load-capacity assessment tools for the military, otherwise known as Military Load Classification (MLC). These tools may be used in the evaluation of the effects of heavy military-vehicles on civilian bridges and are based, in part, on field tests of concrete bridges. This field testing procedure is aimed at determining the MLC ... |
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| The Effects Of Soldiers' Loads on Postural Sway |
DEC 2004 |
9 pages |
| Authors:
Jeffrey M. Schiffman; Carolyn K. Bensel; Leif Hasselquist; Karen Norton; Louis Piscitelle; ARMY NATICK SOLDIER CENTER MA
|
| The purpose of the study was to investigate the effects of load weight and load configurations upon postural sway of Soldiers. Measuring postural sway may complement analyses of walking with loads, allowing for quick and efficient determination of how load carriage gear will impact the Soldier. Fourteen Army enlisted men participated in the study. Postural sway was measured while participants stood on a force platform. Soldiers were tested under four ... |
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| Effects of Variable Contact Load on Fretting Fatigue Behavior of Shot- Peened and Un-Peened Titanium Alloy |
DEC 2004 |
230 pages |
| Authors:
Chia-hwa Lee; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| Fretting fatigue occurs between two components in contact under relative motion and reduces fatigue life when compared with plain fatigue. Shot- peening, on the other hand, is the most commonly used cold working process to improve material fatigue resistance in aeronautical industries. Nearly all work accomplished to date has assumed a constant contact load while investigating fretting fatigue. The primary goal of this study was to explore fretting fatigue behavior ... |
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| Procedure for Determining One-Dimensional Flow Distributions in Arbitrarily Connected Passages Without the Influence of Pumping |
JUN 2004 |
10 pages |
| Authors:
Peter L. Meitner; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| A calculation procedure is presented which allows the one-dimensional determination of flow distributions in arbitrarily connected (branching) flow passages having multiple inlets and exits. The procedure uses an adaptation of the finite element technique, iteratively coupled with an accurate one- dimensional flow solver. The procedure eliminates the usual restrictions inherent with finite element flow calculations. Unlike existing one-dimensional methods, which require simplifications to the flow equations (uncoupling the momentum and ... |
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| An Experimental Investigation into the Temperature Profile of a Compliant Foil Air Bearing |
MAY 2004 |
20 pages |
| Authors:
Kevin Radil; Michelle Zeszotek; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| A series of tests was performed to determine the internal temperature profile in a compliant bump-type foil journal air bearing operating at room temperature under various speeds and load conditions. The temperature profile was collected by instrumenting a foil bearing with nine, type K thermocouples arranged in the center and along the bearing's edges in order to measure local temperatures and estimate thermal gradients in the axial and circumferential directions. ... |
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| SURE-LOK, Style II Container, 40" x 48", MIL-STD-1660 Tests |
MAY 2004 |
25 pages |
| Authors:
Jeffrey L. Dugan; ARMY DEFENSE AMMUNITION CENTER MCALESTER OK VALIDATION ENGINEERING DIV
|
| The U.S. Army Defense Ammunition Center (DAC), Validation Engineering Division (SJ MAC-DEV) conducted MIL-STD-1 660, "Design Criteria for Ammunition Unit Loads" on the SURE-LOK, Style II, 40" x 48", Container manufactured by Action Wood Technologies, Inc., from Clinton Township, Michigan. Two containers were tested. The containers wereCorp Source loaded and passed with a load of 4, 080 lbs and 4,075 lbs, respectively. The tests accomplished on the test units were ... |
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| Transportability Testing of the Marine Corps High Mobility Artillery Rocket System (HIMARS) Resupply Vehicle (RSV) and Resupply Trailer (RST), TP-94- 01, "Transportability Testing Procedures" |
MAY 2004 |
42 pages |
| Authors:
ARMY DEFENSE AMMUNITION CENTER MCALESTER OK VALIDATION ENGINEERING DIV
|
| The U.S. Army Defense Ammunition Center (DAC), Validation Engineering Division (SJMAC-DEV), was tasked by the Marine Corps High Mobility Artillery Rocket System (HI MARS) Liaison Officer to the Program Executive Officer (PEO) Precision Fire Rocket Missile System (PFRMS) to conduct transportability testing on the Marine Corps HIMARS Resupply System (RSS). The RSS consists of the HI MARS Resupply Vehicle (RSV) and the HIMARS Resupply Trailer (RST). The testing was conducted ... |
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| Virtual Testing with Validated Analysis Tools |
27 AUG 2003 |
12 pages |
| Authors:
Craig Collier; Duane Veley; Steve Owens; COLLIER RESEARCH CORP HAMPTON VA
|
| Collier Research Corporation is working with Lockheed Martin Aeronautics (LM Aero) under United States Air Force Research Lab (AFRL) funding to develop a "certification-by-analysis" process to reduce unexpected failures during experimental testing that will, in turn, accelerate Air Force structural certification. The goal is early identification and avoidance of conceptual and preliminary design problems on new and sustaining aircraft programs using a "design-by-analysis" process that includes the commercial structural sizing ... |
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| A Water Tunnel Investigation of a Small Scale Rotor Operating in the Vortex Ring State |
JUN 2003 |
77 pages |
| Authors:
Charles B. Rumsey Jr; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF PHYSICS
|
| Motivation to expand the understanding of a helicopter rotor descending into the vortex ring state (VRS) stems from the aircraft mishaps that have plagued the helicopter community. The V-22 has become the most recent victim of encounters with VRS. The onset of VRS is associated with the collapse of the helical vortex wake in the plane of the rotor. The resulting wake disturbances develop an irregular and aperiodic flow. Rotor ... |
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| Room Temperature Characterization of a Magnetic Bearing for Turbomachinery |
OCT 2002 |
14 pages |
| Authors:
Gerald Montague; Mark Jansen; Andrew Provenza; Ralph Jansen; Ben Ebihara; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| Open loop, experimental force and power measurements of a three-axis, radial, heteropolar magnetic bearing at room temperature for rotor speeds up to 20,000 RPM are presented in this paper. The bearing, NASA Glenn Research Center's and Texas A&M's third generation high temperature magnetic bearing, was designed to operate in a 1000 deg. F (540 deg. C) environment and was primarily optimized for maximum load capacity. The experimentally measured force produced ... |
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| Thermal Interactions in Rolling Bearing Dynamics |
MAR 2002 |
124 pages |
| Authors:
Pradeep K. Gupta; GUPTA (PRADEEP K) CLIFTON PARK NY
|
| Numerical enhancements to the established bearing dynamics computer code, Advanced Dynamics of Rolling Elements (ADORE), have been accomplished for improved computation of bearing heat generation and geometrical variation in bearing element dimensions. Thermal interaction modules have been added to analyze the computed heat generation considering conduction through the element and convection to the circulating fluid or lubricant. Averaging procedures have been implemented to determine the bulk temperatures of the various ... |
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| Measuring Time-Dependent Pavement Deflection Profiles Under Drive-by Conditions with a Portable System |
12 FEB 2002 |
46 pages |
| Authors:
Andres Peekna; James L. Pickens; Jim W. Hall Jr; INNOVATIVE MECHANICS INC CLARENDON HILLS IL
|
| Measuring pavement deflections on secondary roads permits assessment of their performance upon passage of an Army convoy. On secondary roads traffic volume is low enough to permit drive-by conditions. The system was designed accordingly. For sensing pavement deflections, linear variable differential transformer (LVDT) sensors were chosen. The investigation showed that in order to credibly extrapolate from sensors away from the tires to deflection underneath the tires, a laterally separated pair ... |
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| High-Cycle Fatigue Testing of Turbine Blades Under Multiaxial Loading |
DEC 2001 |
82 pages |
| Authors:
Mohan Balan; Bart Bornhorst; Som R. Soni; Ming Xie; ADTECH SYSTEMS RESEARCH INC BEAVER CREEK OH
|
| Gas turbine engine blades are subjected to a centrifugal force in the radial direction and high frequency transverse excitation under operating conditions. A multiaxial loading machine was proposed in the present SBIR program to perform high-cycle fatigue testing on gas turbine engine blades. A GE F110 second stage fan blade was selected as the specimen for initial testing and design studies. The blade was modeled and analyzed using finite element ... |
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| Hi-Fidelity Simulation and Prediction of Helicopter Single Point External Load Stabilization |
SEP 2001 |
205 pages |
| Authors:
George E. Ehlers; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The helicopter has been used since its early development for external transport of large or bulky loads to small austere locations. Among the problems encountered as lift capability and airspeeds increased was that of divergent load oscillations due to load aerodynamics. The most problematic are the single point external loads displaying unsteady aerodynamics and coupled yaw-pendulum modes accounting for the instability of cargo containers. However, a lack of simulation models ... |
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| The Influence of Load Carrying Methods on Gait of Healthy Women |
MAY 2001 |
6 pages |
| Authors:
Wen Ling; Kenneth Axen; Vern Houston; NEW YORK UNIV NY DEPT OF PHYSICAL THERAPY
|
| Various load configurations on healthy men, but not women, have been examined. Women were found to have higher incidence of musculoskeletal injuries when carrying a heavy load during basic training. The purpose of this study was to examine the changes in gait patterns of healthy women while carrying a 10 Kg. load on the back, around the waist, and across one shoulder. The investigators further evaluated the influence of shoulder ... |
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| Material Choices for Good Load Carriage Design |
MAY 2001 |
|
| Authors:
Gareth Davies; DEFENCE CLOTHING AND TEXTILES AGENCY ESSEX (UNITED KINGDOM)
|
| The paper discusses the selection of fabrics, webbing, tapes, sewing threads and the issues that surround their choice in the military scenario. How infrared signature is achieved on synthetic materials, so that service personnel are hidden from night sights, is explained. A weldable material has been identified in the UK offering the opportunity to produce waterproof rucksacks. The choice of interface materials to the body is discussed and the new ... |
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| Biomechanical Assessment of Lateral Stiffness Elements in the Suspension System of a Rucksack |
MAY 2001 |
|
| Authors:
S. A. Reid; R. A. Whiteside; QUEEN'S UNIV KINGSTON (ONTARIO) SCHOOLOF PHYSICAL AND HEALTH EDUCATION
|
| The purpose of this study was to examine the change in load distribution characteristics associated with adding lateral stiffness elements (rods) to a rucksack. A manikin was instrumented to allow determination of the load applied to the shoulders and upper torso independent of the load applied to the hips and lower trunk. Position and mass of the payload (25 kg) was fixed at the centre of the volume of the ... |
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| Analysis of SRPT Scheduling: Investigating Unfairness |
JUL 2000 |
25 pages |
| Authors:
Nikhil Bansal; Mor Harchol-Balter; CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE
|
| The Shortest-Remaining-Processing-Time (SRPT) scheduling policy has long been known to be optimal for minimizing mean response time. Despite this fact, SRPT scheduling is rarely used in practice. It is believed that the performance improvements of SRPT over other scheduling policies with respect to mean response time stem from the fact that SRPT unfairly penalizes the large jobs in order to help the small jobs. This ... |
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| Enhancement to Repair Assessment Procedure and Integrated Design (RAPID) . Analysis Methods Enhancements |
JUN 2000 |
319 pages |
| Authors:
Chun Chen; Miles Nomura; Jin Yu; BOEING CO LONG BEACH CA
|
| This document describes the technical details of the analysis methodology used in the static and damage tolerance analysis modules of the Repair Assessment Procedure and Integrated Design (RAPID) program. In this document, the static strength analysis method for repaired fuselage skin and skin modifications to antenna installation is first described. Next, a description of the damage tolerance method is provided. This document also includes descriptions of the methods developed for ... |
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| Formation of Nanostructured Surface Regions Under a Concentrated Load |
2000 |
|
| Authors:
M. SH. Akchurin; V. R. Regel; RUSSIAN ACADEMY OF SCIENCES MOSCOW INST OF CRYSTALLOGRAPHY
|
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| Advances in Structural Loadflow Visualisation and Applications to Optimal Shapes |
OCT 1999 |
|
| Authors:
W. Waldman; M. Heller; L. R. Rose; AERONAUTICAL AND MARITIME RESEARCH LAB MELBOURNE (AUSTRALIA)
|
| Currently there is no generally accepted procedure for calculation of structural loadpaths, which would show how remote loads are equilibrated through a structure and could provide insight into how well a structure is performing its intended load-carrying functions. Kelly and Elsley have recently proposed a method for computing loadflow orientations and loadpaths using finite element results, which is based on iterative solutions of non-linear equations. In this ... |
|
| Studies of Time-Phased Vertical and Lateral Gusts: Development of Multiaxis One-Minus-Cosine Gust Model |
OCT 1999 |
61 pages |
| Authors:
J. G. Jones; STIRLING DYNAMICS INC SEATTLE WA
|
| At a Gust Specialists meeting convened by the Federal Aviation Administration (FAA) in 1998, a multiaxis extension of the existing tuned isolated discrete-gust (IDG) method (1-cosine profile) incorporating a pair of vertical and lateral one-minus-cosine gusts was proposed. A particular application of this method is the gust response of wing-mounted nacelles. This report presents the theoretical and empirical basis for this gust model, including ... |
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| Inlet Flow Distortion and Unsteady Blade Response in a Transonic Axial- Compressor Rotor |
10 SEP 1999 |
9 pages |
| Authors:
D. C. Rabe; C. Williams; C. Hah; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| This paper describes the unsteady blade surface pressures on the first-stage rotor blades of a two-stage transonic axial flow compressor experiencing inlet flow distortion. This study was conducted to demonstrate the ability of a full annulus unsteady Reynolds-averaged Navier-Stokes numerical technique to predict unsteady pressures on the rotor blades operating in a distorted inflow. A total pressure distortion produced by a variable mesh screen mounted ... |
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| Leapfrog Technology to Standardize Equipment and System Installations. Section Number 2 - Equipment, System Installation, and Technical Criteria |
SEP 1999 |
12 pages |
| Authors:
Dominic Burns; John Hopkinson; NATIONAL STEEL AND SHIPBUILDING CO SAN DIEGO CA
|
| This sub-task report provides a description of the design requirements and engineering criteria to be used in the development of the equipment installation standards. |
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| Statistical Analysis of Atmospheric Flight Gust Loads Analysis Data |
JUL 1999 |
28 pages |
| Authors:
J. B. Clark; M. C. Kim; A. M. Kabe; AEROSPACE CORP EL SEGUNDO CA ENGINEERING AND TECHNOLOGY GROUP
|
| To establish launch vehicle loads during atmospheric flight, the statistical characteristics of the turbulence/gust-induced loads need to be determined. Recently, a Monte Carlo analysis procedure was developed that uses measured turbulence/gusts to establish launch vehicle loads. This paper presents the procedures developed to characterize the distribution of the data and to calculate tolerance bounds on these Monte Carlo loads. |
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| Comparison of Boundary Correction Factor Solutions for Two Symmetric Cracks in a Straight-Shank Hole |
APR 1999 |
22 pages |
| Authors:
John G. Bakuckas Jr; FEDERAL AVIATION ADMINISTRATION ATLANTIC CITY NJ AIRPORT AND AIRCRAFT SAFETY RESEARCH AND DEVELOPMENT
|
| This report compares the mode 1 boundary correction factor solutions for two symmetric elliptical cracks emanating from a straight-shank hole. A variety of methods were used to generate the solutions. A global-intermediate- local (GIL) hierarchical approach was developed using the finite element method (FEM). Comparisons were made with the following methods: the FEM with the equivalent domain integral, semiempirical boundary correction factor equations, the finite element alternating method, the boundary ... |
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| Limit Analysis of Frictional Block Assemblies as a Mathematical Program With Complementarity Constraints |
15 FEB 1999 |
24 pages |
| Authors:
M. C. Ferris; F. Tin-Loi; WISCONSIN UNIV-MADISON DEPT OF COMPUTERSCIENCES
|
| The computation of the collapse loads of discrete rigid block systems, characterized by frictional (nonassociative) and tensionless contact interfaces, is formulated and solved as a special constrained optimization problem known as a Mathematical Program with Equilibrium Constraints (MPEC). In the present instance, some of the essential constraints are defined by a complementarity system involving the orthogonality of two sign-constrained vectors. Due to its intrinsic ... |
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| A Cockroach-Like Hexapod Robot for Natural Terrain Locomotion |
18 DEC 1998 |
5 pages |
| Authors:
Randall D. Beer; CASE WESTERN RESERVE UNIV CLEVELAND OHOFFICE OF RESEARCH ADMINISTRATION
|
| This performance report describes progress over the last 6 months in 3 areas: (1) robotics, (2) physiology, and (3) modeling. |
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| Tribological Modeling |
OCT 1998 |
138 pages |
| Authors:
Pradeep K. Gupta; GUPTA (PRADEEP K) CLIFTON PARK NY
|
| Analytical modeling of tribological behavior of interacting bodies is undertaken in three parts: modeling stresses at the surface and in the coatings of a coated solid, friction or traction at the interface between two contacting solids, and modeling of wear under given conditions of operation. Stress modeling of coated solids is accomplished by plane strain numerical solutions for line contact problems and finite element solutions of ... |
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| Ballast System for Underwater Vehicle |
14 JUL 1998 |
9 pages |
| Authors:
Daniel W. French; Theodore C. Gagliardi; Steven L. Camara; John J. Vaillancourt; David Nugent; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A ballast weight system for releasably attaching a ballast weight to an underwater vehicle is disclosed where the system comprises a ballast weight, a housing disposed about the ballast weight, a fairing connected to the ballast weight to facilitate a flush connection of the ballast weight to the underwater vehicle, and a bolt coupler where one end of the bolt receives a lanyard pin there through and the second end ... |
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| Prediction of Extreme and Fatigue Sea Loads Using Linear Theory |
JUN 1998 |
|
| Authors:
Kevin A. McTaggart; DEFENCE RESEARCH ESTABLISHMENT ATLANTICDARTMOUTH (NOVA SCOTIA)
|
| This report presents three different approaches for determining exceedence probabilities of ship sea loads using linear strip theory. The first two approaches use nominal maximum loads for hourly and variable duration seaways, while a third approach considers individual load cycle amplitudes in all seaways. Of the three approaches, the load cycle approach appears to be most useful and can be used for both fatigue and ultimate ... |
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| Stress Concentration Around a Patched Hole in an Axi-Symmetrically Loaded Plate |
JUN 1998 |
|
| Authors:
C. Pickthall; L. R. F. Rose; AERONAUTICAL AND MARITIME RESEARCH LAB MELBOURNE (AUSTRALIA)
|
| This paper examines the efficiency of an adhesively bonded reinforcement patch in reducing the stress concentration around a hole in a plate, as a function of hole size. Differential equations are derived for the radial and tangential displacements in the plate and reinforcement assuming only in plane stresses without out of plane bending. Imposition of angular independence leads to distinct load transfer lengths for ... |
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| Elastic Comparison of Four Thread Forms |
FEB 1998 |
29 pages |
| Authors:
G. P. O'Hara; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| Previously, this author introduced the concept that all screw thread forms have a structural Characteristic Curve, which defines the basic stress concentration as a function of a radial stress in the joint. An additional set of characteristic curves is produced when the general stress field is considered. The standard analysis is for a single thread tooth, isolated from a long chain of identical teeth, that is computationally efficient and facilitates ... |
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| Pressure/Temperature Logger (PTL) Development and Field Deployment for the Great Bay, NH, Tidal Dynamics Experiment |
JAN 1998 |
|
| Authors:
Carl T. Friedrichs; Wayne D. Spencer; David G. Aubrey; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
|
| During 1992 and 1993 experiments were conducted in the shallow east side of Great Bay, New Hampshire. These experiments were conducted to better understand the morphodynamics and evolutionary tendencies of shallow tidal embayments and intertidal flats. Hardware and software used in the collection of data are described. Discussed also are techniques used to collect data. Six pressure temperature loggers (PTL) and one current meter (TCSWG) were ... |
|
| Vertical Lift Gates |
30 NOV 1997 |
61 pages |
| Authors:
CORPS OF ENGINEERS WASHINGTON DC
|
| The purpose of this manual is to provide guidance in the structural design of vertical lift gates. This manual applies to all USACE Commands having responsibility for design of civil works projects. Several types of vertical lift gates are used in a variety of hydraulic structures, including spillways, low level inlets/outlets, powerhouses, and navigation locks. In recent years, there have been considerable problems with the performance of vertical lift gates. ... |
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| Method for Determining the Approximate Resonance Frequency of a Structure Surrounded by a Compressible Fluid. |
11 NOV 1997 |
|
| Authors:
Michele D. McCollum; Clementina M. Siders; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A method for determining the approximate resonance frequency of a structure surrounded by a compressible fluid includes the steps of: (1) performing analysis to determine in-vacuo frequencies and mode shapes of the structure; (2) selecting an in-vacuo mode of interest; (3) computing an influence matrix at the eigenfrequency of the selected mode of interest; (4) combining the computed influence matrix with structural stiffness and mass matrices from a finite element ... |
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| Nonlinear Finite Element Analyses of Damaged Stiffened Panels |
NOV 97 |
|
| Authors:
Thomas S. Hu; DEFENCE RESEARCH ESTABLISHMENT ATLANTICDARTMOUTH (NOVA SCOTIA)
|
| Ship hulls suffer various types of damage during operation. This damage can be corrosion caused by the marine environment or dents resulting from external forces. In order to make efficient repair decisions, residual strength of the damaged component needs to be assessed. The assessment can be carried out with numerical models such as nonlinear finite element methods or simplified approaches, but this requires experimental verification. DREA conducted a joint stiffened ... |
|
| Intermodule Connector Technology for Mobile Offshore Base Structures |
SEP 97 |
4 pages |
| Authors:
MAINE UNIV AT ORONO
|
| The objectives for the work under this grant continue to be: (1) Determination of design requirements for Mobile Offshore Base (MOB) connectors and development of accurate, reliable predictions of connector performance; (2) Further development of concepts for flexible intermodule connectors and evaluation using computational modeling; and (3) Proof of concept for selected configurations through fabrication and scale model testing of most promising connector concepts. |
|
| A Microprocessor-Based Gradient Analyser for F/A-18 Bulkhead Spectrum Loading |
SEP 97 |
|
| Authors:
Leopold Sponder; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION CANBERRA (AUSTRALIA)
|
| This report describes a specially designed instrument that was used during a full scale fatigue test of an F/A-18 bulkhead to support the acquisition and analysis of acoustic emission (AE) data for the investigation of crack initiation and growth. This device, developed by the author, comprises both hardware and software and generates binary data in real time that indicates the sign of the gradient of an applied spectrum load signal. ... |
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| A Finite-Element Model for the Olmsted Wicket |
AUG 97 |
110 pages |
| Authors:
Mostafiz R. Chowdhury; Sharon Garner; Yazmin Seda-Sanabria; Robert L. Hall; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS STRUCTURES LAB
|
| This report presents the step-by-step updating procedures to develop an analytical finite element (FE) model of the Olmsted wickets. The FE model was validated using results obtained from both dry and wet experimental modal analyses and static and flow-induced dynamic experiments. Geometric dimensions, physical properties, and experimental modal data were correlated with the analytical model to ensure the correct distribution of mass and stiffness of the model. Wet modal parameters ... |
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| Remedial Measures for Downstream Outlet Wall, Hopkinton Dam Merrimack River Basin, NH |
JUL 1997 |
113 pages |
| Authors:
Reginald Pretto; CORPS OF ENGINEERS WALTHAM MA NEW ENGLAND DIV
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| The right side (east) outlet wall which separates the forebay pool from the stilling basin has been displaying consistent movement since construction of the dam. Measurements taken have shown that the movement is a combination of both frost action and lateral loading due to earth pressure. This report describes the types of measurements taken, the results and conclusions drawn from those measurements, and a discussion ... |
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| Efficient Parallel Semantic/O-O Database Management |
06 JUN 1997 |
49 pages |
| Authors:
Naphtali Rishe; FLORIDA INTERNATIONAL UNIV MIAMI SCHOOL OF COMPUTER SCIENCE
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| We have developed an optimistic concurrency control method for a massively parallel semantic database machine. Our concurrency control algorithm achieves very fine granularity, ensures serializability and external consistency, and uses local logical clocks which do not require physical clock synchronization. We have also developed a dynamic load balancing algorithm which repartitions data among processors using a fault-tolerant data transfer policy to produce a more evenly balanced load. We have implemented ... |
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