| An Experimental Study of Fiberglass Composites Containing Metal Wire Joints |
Sep-2009 |
54 pages |
| Authors:
Joseph E Klopfer; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
 | The U.S. Navy has been incorporating increasing amounts of composite materials during construction, especially in the areas of submarine sails and surface ship superstructures. The benefit of using composite material with metal wire layers imbedded is that these metal wire layers may be welded to the steel superstructure of a Naval Vessel resulting in maximum joint strength. Joining a composite structure to a metallic structure required the metal-wire layers to ... |
|
| Finite Element Analyses and Experimental Testing of Hybrid Composite/Metal Joints Subjected to Fully Reversed Flexure Fatigue Loading |
30-Aug-2009 |
173 pages |
| Authors:
Vincent Caccese; Douglas Dow; Senthil S Vel; MAINE UNIV AT ORONO DEPT OF MECHANICAL ENGINEERING
|
| The goal in this research is to accurately assess the fatigue life of hybrid composite/metal connections focusing upon bolted joints used in removable panels. Experimental testing was performed in flexure fatigue as part of this effort and is essential for fatigue life evaluation. In addition, analytical studies were performed using finite element analysis. Existing finite element modeling software offers a robust method for assessing the structural integrity of proposed hybrid ... |
|
| Medical Surveillance Monthly Report. Volume 16, Number 7, July 2009 |
Jul-2009 |
21 pages |
| Authors:
ARMED FORCES HEALTH SURVEILLANCE CENTER SILVER SPRING MD
|
| Lyme disease is a zoonotic tick-borne disease that is caused by infection with a spirochetal bacterium of the genus Borrelia. It has a worldwide distribution and is endemic in many temperate regions of the northern hemisphere. In the United States, it is hyperendemic along the mid- and northeastern Atlantic seaboard and in nonurban areas of Wisconsin. Lyme disease is transmitted by ticks that feed on both humans and animal hosts ... |
|
| Pathogenesis of Heterotopic Ossification in Traumatic Brain Injury |
01-Apr-2009 |
12 pages |
| Authors:
Frederick P Heinzel; Xin Li; JAMES A HALEY VA HOSPITAL TAMPA FL
|
| Heterotopic ossification (HO) is the pathologic formation of bone in soft tissues. HO develops during the physical rehabilitation of patients with traumatic injuries, such as brain, spinal cord or orthopedic injury. When adjacent to joints or pressure points, HO causes pain, pressure sores and physical obstruction that significantly limits rehabilitation. The incidence is as high as 50% after traumatic amputation due to blast injury, when the amputation is through damaged ... |
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| Demonstration and Validation of Technologies to Mitigate Corrosion on Infrastructure Components at Fort Bragg: Initial Results |
Feb-2009 |
30 pages |
| Authors:
Vincent Hock; Michael Miller; Richard Lampo; Robert Mason; Mark Singleton; Larry Gintert; Kevin Klug; CONCURRENT TECHNOLOGIES CORP ALEXANDRIA VA
|
| A briefing on technologies used to mitigate corrosion on the mechanical room piping system and the cooling tower pumps at Fort Bragg, NC. |
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| Study of Composite Joint Strength with Carbon Nanotube Reinforcement |
01-Sep-2008 |
70 pages |
| Authors:
Susan D Faulkner; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Strengthening of composite joints is a topic of recent research. The benefits of using locally applied carbon nanotubes to reinforce a carbon fiber composite joint were studied. The effect of carbon nanotubes on enhancing the fracture toughness and joint interface strength was investigated by performing Mode I, Mode II, and Mixed Mode I/Mode II fracture with and without carbon nanotubes applied locally at the joint interface. Furthermore, the effects of ... |
|
| Enhancing the Interfacial and Dynamic Failure Behavior of Advanced Hybrid Structures Using Nanocomposite Materials |
08 AUG 2007 |
16 pages |
| Authors:
Luoyu R. Xu; VANDERBILT UNIV NASHVILLE TN DIV OF SPONSORED RESEARCH
|
| A novel interfacial joint was developed for reducing the interfacial stress levels. The proposed design, inspired by the shape and mechanics of trees, effectively removed the stress singularity at the interfacial joint for most engineering materials through an integrated theoretical and experimental investigation. Significant tensile loading capacity increase was obtained (up to 81%) using this new joint, while the material volume of the new joint actually was reduced. Dynamic tension ... |
|
| Processing and Characterization of NiTi Shape Memory Alloy Particle Reinforced Sn-In Solders |
DEC 2006 |
73 pages |
| Authors:
Kohn C. Chung; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| In the typical packaging of a printed circuit board, the tiny-yet-critical solder joints provide both electrical connection and mechanical support for the silicon chips and their substrate. These solders are subjected to serve thermo-mechanical strains during usage and the most common failure arise from thermo-mechanical fatigue (thermal cycling). This is due to the mismatch in the coefficient of thermal expansion between the chip and the packaging substrate. In previous work, ... |
|
| Improved Buttress Thread Machining for the Excalibur and Extended Range Guided Munitions |
21 APR 2006 |
2 pages |
| Authors:
NATIONAL CENTER FOR DEFENSE MANUFACTURING AND MACHINING LATROBE PA
|
| Raytheon Missile Systems (Raytheon) of Tucson, Arizona, manufacturer of the Excalibur and Extended Range Guided Munitions (ERGM) have consistently received critical components containing Class III, 7 degree/45 degree buttress threads out-of-tolerance from their suppliers. These out-of-tolerance conditions have caused failures of the components at the buttress thread joints. The Rockwell hardness of the 4340 steel (Rc53) being used for the components is a major contributor to the out-of-tolerance condition. The ... |
|
| Biologically-Inspired Microrobots. Volume 3. Micro-Robot Based on Abstracted Biological Principles |
APR 2006 |
61 pages |
| Authors:
Roger D. Quinn; Roy E. Ritzmann; Jeremy Morrey; Andrew Horchler; CASE WESTERN RESERVE UNIV CLEVELAND OH
|
| This is one of three reports on the study of micro-robots. This document describes the development of novel highly mobile small robots called "Mini-Whegs" that can run and jump. They are derived from our larger Whegs series of robots, which benefit from abstracted cockroach locomotion principles. Key to their success are the three-spoke appendages, called wheel-legs, which combine the speed and simplicity of wheels with the climbing mobility of legs. ... |
|
| Muzzle Exit (Set Forward) Effects on Projectile Dynamics |
APR 2006 |
14 pages |
| Authors:
D. Carlucci; J. Cordes; S. Morris; R. Gast; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ TECHNICAL RESEARCH CENTER {DUPLICATE#1}
|
| Set forward is a highly dynamic condition that occurs when a projectile exits the muzzle of a weapon. The levels of this acceleration, as well as the frequency, are dependent upon the projectile structural characteristics, length, and muzzle exit pressure. The set forward event can not, in general, be modeled using quasi static techniques. A dynamic analysis must be performed, especially for sensitive electronic components. Proper inspection of critical joints ... |
|
| Biomimetic Design of an Under-Actuated Leg Exoskeleton for Load-Carrying Augmentation |
01-Feb-2006 |
97 pages |
| Authors:
Conor J Walsh; MASSACHUSETTS INST OF TECH CAMBRIDGE MEDIA LAB
|
| Metabolic studies have shown that there is a metabolic cost associated with carrying a load. Previous work on exoskeleton design has not considered the passive dynamics of walking and has focused on fully actuated systems that are inefficient and heavy. In this thesis, an underactuated exoskeleton is presented that runs parallel to the human leg. The exoskeleton component design is based on the kinematics and kinetics of human walking. The ... |
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| Ram Load Simulation of Wing Skin-Spar Joints: New Rate-dependent Cohesive Model |
06 JAN 2006 |
79 pages |
| Authors:
Monty A. Moshier; RHAMM TECHNOLOGIES LLC BELLBROOK OH
|
| A new rate-dependent cohesive zone model for use in impact and/or hydrodynamic ram delamination problems is presented. The traction based model includes a damage-dependent term and two cohesive zone viscosity parameters. The first viscosity parameter adjusts the yield traction of the material, while the second parameter adjusts the peak or maximum traction. This new rate-dependent cohesive model is implemented in Ls-DYNA (971 beta revision 5397), an explicit time integration FEA ... |
|
| Fracture Flow Research, Volume 1: Modeling Rock Fracture Intersections - Application in the Boston Area and Estimation of the Well-Test Flow Dimension |
28 SEP 2005 |
341 pages |
| Authors:
Jean Louis Z. Locsin; Herbert H. Einstein; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CIVIL AND ENVIRONMENTAL ENGINEERING
|
| Fractures govern flow, deformation and strength of rock masses. Fracture flow is important with regard to resource extraction (water, gas, oil) as well as groundwater contamination. Fractures through their effect on deformability and strength govern stability of tunnels and slopes in rock and the behavior of building,-, bridge - and dam foundations. Very importantly, they also strongly affect penetration resistance. The research consisted of two components, modeling of joint (fracture) ... |
|
| Fracture Flow Research, Volume 2: Modeling Joint Patterns Using Combinations of Mechanical and Probabilistic Concepts |
28 SEP 2005 |
530 pages |
| Authors:
Jean Louis Z. Locsin; Herbert H. Einstein; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CIVIL AND ENVIRONMENTAL ENGINEERING
|
| Fractures govern flow, deformation and strength of rock masses. Fracture flow is important with regard to resource extraction (water, gas, oil) as well as groundwater contamination. Fractures through their effect on deformability and strength govern stability of tunnels and slopes in rock and the behavior of building,-, bridge - and darn foundations. Very importantly, they also strongly affect penetration resistance. The research consisted of two components, modeling of joint (fracture) ... |
|
| Biologically-Inspired Micro-Robots: Volume 2: Investigation of a Micro-Joint Angle Sensor Using MEMS Cilia |
SEP 2005 |
43 pages |
| Authors:
Gary K. Fedder; Lauren E. de Rosset; CASE WESTERN RESERVE UNIV CLEVELAND OH
|
| This is one of three reports on the study of micro-robots. This document describes the design and fabrication of a joint angle sensor composed of an array of curled, directionally-sensitive MEMS cantilever beams with piezoresistive sense elements, analogous to an insect hair plate. The sensor is to be embedded in the limb such that the surface of the chip is flush with the surface of the limb. Actuation is then ... |
|
| Adaptive Nonlinear Tracking Control of Kinematically Redundant Robot Manipulators with Sub-Task Extensions |
2005 |
14 pages |
| Authors:
E. Tatlicioglu; M. McIntyre; D. Dawson; I. Walker; CLEMSON UNIV SC DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| Past research efforts have focused on the end-effector tracking control of redundant robots because of their increased dexterity over their non-redundant counterparts. This work utilizes an adaptive full-state feedback quaternion based controller developed in [5] and focuses on the design of a general sub-task controller. This sub-task controller does not affect the position and orientation tracking control objectives, but instead projects a preference on the configuration of the manipulator based ... |
|
| Uncertainties and Relaxation of Boundary Conditions of Aeroelastic Panels |
08 NOV 2004 |
34 pages |
| Authors:
Raouf A. Ibrahim; WAYNE STATE UNIV DETROIT MI DEPT OF MECHANICAL ENGINEERING SCIENCES
|
| The influence of boundary condition relaxation on two-dimensional panel flutter is studied in the presence of in-plane loading. The boundary value problem of the panel involves time-dependent boundary conditions that are converted into autonomous form using a special coordinate transformation. Galerkin's method is used to discretize the panel partial differential equation into six nonlinear ordinary differential equations representing the first six modes. The influence of boundary condition relaxation on the ... |
|
| Dielectric Non-Destructive Analysis of Adhesive Bonded Structures |
28 SEP 2004 |
148 pages |
| Authors:
Jovan Mijovic; POLYTECHNIC UNIV BROOKLYN NY
|
| An investigation was conducted aimed at developing dielectric spectroscopy as a non-destructive inspection tool to assess aging of adhesive bonded structures. Dielectric spectroscopy was found to be a sensitive tool capable of detecting defects and absorbed moisture in adhesive bonded structures. The highlights of the research performed are: l) The defects in adhesive joints decrease the real and imaginary dielectric permittivity in the frequency domain and induce additional peaks in ... |
|
| Implementation of a Human Avatar for the MARG Project in Networked Virtual Environments |
MAR 2004 |
78 pages |
| Authors:
Faruk Yildiz; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The objective of the ongoing MARG project is to animate human motions captured by 15 MARG sensors in wireless networked virtual environment (NVES). Three avatars were developed previously, but none of them met all the desired requirements. The first one was overly simplistic and did not implement H-Anim standards. The other two were created using laser-scanned data and followed the H-Anim standards, but one had its adjacent joints broken and ... |
|
| Design and Testing of the Minotaur Advanced Grid-Stiffened Fairing |
2004 |
11 pages |
| Authors:
John Higgins; Peter Wegner; Adrian Viisoreanu; Greg Sanford; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
| A composite grid-stiffened structure concept was selected for the payload fairing of the Minotaur launch vehicle. Compared to sandwich structures, this concept has an advantage of smaller manufacturing costs and lighter weight. To reduce weight the skin pockets are allowed to buckle visibly up to about 0.5 cm peak displacement. Various failure modes were examined for the composite grid-stiffened structure. The controlling criterion for this design was a joint failure ... |
|
| Testing of a Delta IV Payload Attach Fitting (PAF) Substructure With an Integral Composite Flange |
2004 |
9 pages |
| Authors:
John E. Higgins; Greg Sanford; Jeffry S. Welsh; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
| The Air Force Research Laboratory Space Vehicles Directorate (AFRL/VS) has developed a unique composite Payload Attach Fitting (PAF) shell design Alliant Techsystems (ATK) and the Boeing Company Huntington Beach CA have developed manufacturing processes and a shell design that incorporates an all-composite forward flange with transverse reinforcement (Z-pinning) at key locations to prevent transverse separation and failure under high bending loads. This paper describes testing equipment instrumentation and procedures developed ... |
|
| Medical Surveillance Monthly Report (MSMR). Volume 9, Number 7, November/December 2003 |
Dec-2003 |
21 pages |
| Authors:
ARMED FORCES HEALTH SURVEILLANCE CENTER SILVER SPRING MD
|
| The knee is a hinge joint whose stability and function are maintained by four ligaments that attach the femur to the tibia. The cruciate ligaments (anterior and posterior) are short fibrous cords that cross each other inside the joint. They prevent forward and backward movements of the tibia under the femur and guide the tibia over the end of the femur throughout the knee's range of motion. When cruciate ligaments ... |
|
| Innovative Engineers Pave New Paths in Afghanistan |
Dec-2003 |
4 pages |
| Authors:
Steven A Baker; AIRBORNE DIV ( 82ND) FORT BRAGG NC
|
| As Operation Enduring Freedom moves into its second year, the engineers in Afghanistan have moved beyond initial-entry operations. They have started to attack some of the daunting general engineering and mobility challenges posed by this arid and austere environment. The 82d Airborne Division's 307th Engineer Battalion airfield repair team at Kandahar International Airport has introduced several construction initiatives in runway repair that will not only prolong the life span of ... |
|
| Low Temperature Active Joining of Structural and Electronic Composites |
15 JUL 2003 |
64 pages |
| Authors:
Ronald W. Smith; Travia Nelson; MATERIALS RESOURCES INTERNATIONAL LANSDALE PA
|
| This report covers the technical work conducted under contract DASG60-00-C-0056. MRi has successfully completed an evaluation of its active solder joining technology (S-Bond) for joining lightweight aluminum matrix ceramic composites (Al-MMC), such as Al-SiC. This joining technology has been shown to have application in a range of applications for space platform structures and electronics, where Al-MMC's are finding application. S-Bond joining has joint capability from 190 - 350 C, depending ... |
|
| Functional Interactions of Human Rad54 With the Rad51 Recombinase |
MAY 2003 |
41 pages |
| Authors:
Stephen J. Van Komen; TEXAS UNIV HEALTH SCIENCE CENTER AT SANANTONIO
|
| Chromosomal DNA breaks occur in cells during normal metabolism and are induced by continual exposure to harmful radiation and other environmental insults. Homologous recombination represents a major pathway for the elimination of these chromosomal breaks. As such, homologous recombination is indispensable for the maintenance of genome stability in all organisms. Importantly, emerging evidence implicates the homologous recombination machinery in the suppression of cancer formation. In fact, defective homologous recombination represents ... |
|
| Multifunctional Mechatronic Materials |
21 FEB 2003 |
|
| Authors:
Anthony Evans; PRINCETON UNIV NJ OFFICE OF RESEARCH AND PROJECT ADMINISTRATION
|
 | Contributions have been made in two basic areas: ultralight structures based on sandwich panels with truss and textile cores, and high authority actuating structures based on the properties of the Kagome system. This final report contains the following studies: (1) Effective Properties of the Octet-truss Lattice Material, by V.S. Deshpande, N.A. Fleck, and M.F. Ashby; (2) Kagome Plate Structures for Actuation, by R.G. Hutchinson, N. Wicks, A.G. Evans, N.A. Fleck, ... |
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| Functional Range of Motion During GRASP: Impact of the Object Location |
25 OCT 2001 |
|
| Authors:
Mirjana B. Popovic; Dejan B. Popovic; Nebojsa Ralevic; AALBORG UNIV (DENMARK) CENTER FOR SENSORY-MOTOR INTERACTION
|
| In this study we determined the Functional Range of Motion (F_ROM) of arm and hand joints for various functional tasks and different locations of the objects to be grasped. The data for F_ROM were collected in six healthy volunteers who used seven selected objects typical for daily activities. Subjects grasped the objects from six different locations marked at the working desk. The recorded data comprised nine hand and arm joint ... |
|
| Load-Speed Interaction Effects on the Biomechanics of Backpack Load Carriage |
MAY 2001 |
16 pages |
| Authors:
Evertt Harman; Ki-Hoon Han; Peter Frykman; ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA
|
| We biomechanically examined how backpack load and walking speed interact in their effects. 16 males walked under all 12 combinations of 6, 20 , 33 and 47 kg backpack loads and 117,133 and 1.50 m/s walking speeds. Generally, the effects of load were consistent over the speeds, and the effects of speed were consistent over the loads. Ground reaction forces and impulses, joint forces, muscle torques, muscle electrical activity and ... |
|
| Effects of Surface Preparation on Long-Term Durability of Composite Adhesive Bonds |
APR 2001 |
24 pages |
| Authors:
Jason Bardis; Keith Kedward; CALIFORNIA UNIV SANTA BARBARA DEPT OF MECHANICAL AND ENVIRONMENTAL ENGINEERING
|
| The long-term effects of surface preparation techniques for composite bonded joints are addressed. Several potential factors are evaluated, concentrating on the effects of peel plies and grit blasting on the fracture toughness and failure mode of adhesively bonded composites. An evaluation of the floating roller peel test configuration is described, where the intent was to extract quantitative data from this commonly used quality control test method. Subsequently, an alternate form ... |
|
| Stress Analysis of In-Plane, Shear-Loaded, Adhesively Bonded Composite Joints and Assemblies |
APR 2001 |
36 pages |
| Authors:
Hyonny Kim; Keith Kedward; CALIFORNIA UNIV SANTA BARBARA DEPT OF MECHANICAL AND ENVIRONMENTAL ENGINEERING
|
| Recent small aircraft that have been certified in the United States, such as the Cirrus SR2O and the Lancair Columbia 300, share similar structural attributes. Specifically, they are both of nearly all-composite construction and both make extensive use of adhesive bonding as a primary method for forming structural joints. Adhesive bonding has potential for being a simple and cost- effective means by which large built-up structures can be assembled. Challenges ... |
|
| Thermal Analysis of a Carbon Fiber Rope Barrier For Use in the Reusable Solid Rocket Motor Nozzle Joint-2 |
MAR 2001 |
9 pages |
| Authors:
J. L. Clayton; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HUNTSVILLE AL GEORGE C MARSHALL SPACE FLIGHT CENTER
|
| This study provides development and verification of analysis methods used to assess performance of a carbon fiber rope (CFR) thermal barrier system that is currently being qualified for use in Reusable Solid Rocket Motor (RSRM) nozzle joint-2. Modeled geometry for flow calculations considers the joint to be vented with the porous CFR barriers placed in the "open" assembly gap. Model development is based on a 1-D volume filling approach where ... |
|
| Viton B O-Ring Resilience Study |
26 JAN 2001 |
49 pages |
| Authors:
T. W. Giants; AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS
|
| The Challenger accident in January 1986 was attributed to failure of the pressure seal in the aft field joint of the solid rocket motor. It was concluded that the elastomeric O-ring seals did not perform their sealing function because of the low temperatures at launch. Because the Shuttle and Titan O-rings were both made of Viton, there was concern that the O-rings on the segment tang and clevis joints on ... |
|
| Nonlinear, Incremental Structural Analysis of Zintel Canyon Dam |
SEP 2000 |
83 pages |
| Authors:
Robert E. Hollenbeck; Stephen B. Tatro; CORPS OF ENGINEERS WALLA WALLA WA WALLA WALLA DISTRICT
|
| This paper presents the time-history thermal analysis of Zintel Canyon Dam, a structure of approximately 70,000 cubic yards of roller compacted concrete (RCC). This study was initiated to demonstrate the implementation of the superseded ETL 1110-2-324, "Special Design Provisions for Massive Concrete Structures," as applied to RCC structures. The results of the study were published in ETL 1110-2- 536, dated December 31, 1994, which should be used as guidance when ... |
|
| Preliminary Material Properties Handbook. Volume 2: SI Units |
01 JUL 2000 |
|
| Authors:
Jana Jackson; Richard Rice; BATTELLE COLUMBUS OH
|
| The Emerging Materials program provides the aerospace industry with typical properties of emerging materials and other materials of interest that have not met all the criteria for inclusion in the MIL-HDBK-5. Materials included in this report are standardized with regard to composition and processing methods and are described by industry, government, or company specifications. |
|
| Carbon Equivalent (Pcm) Limits for Thick Carbon and Low Alloy Steels |
04 APR 2000 |
81 pages |
| Authors:
Jack H. Devletian; OREGON GRADUATE INST BEAVERTON
|
| Experimentally determined preheating/interpass temperatures necessary to prevent hydrogen-assisted cracking of restrained butt welds were established and compared to the best algorithms available to predict such cracking. Weldability tests on large-size plates of ABS & MIL-S-22698 Grades B D and DH-36 as well as ASTM A612 steels were conducted at Electric Boat Corporation using three different plate thicknesses three welding procedures and two levels of diffusible hydrogen. The plate thicknesses were ... |
|
| Preliminary Material Properties Handbook, English Units |
DEC 1999 |
203 pages |
| Authors:
Jana Jackson; Richard Rice; BATTELLE MEMORIAL INST COLUMBUS OH
|
| The Emerging Materials program provides the aerospace industry with typical properties of emerging materials and other materials of interest that have not met all the criteria for inclusion in the MIL-HDBK-5. Materials included in this report are standardized with regard to composition and processing methods and are described by industry, government, or company specifications. |
|
| Preliminary Material Properties Handbook, SI Units |
DEC 1999 |
203 pages |
| Authors:
Jana Jackson; Richard Rice; BATTELLE MEMORIAL INST COLUMBUS OH
|
| The Emerging Materials program provides the aerospace industry with typical properties of emerging materials and other materials of interest that have not met all the criteria for inclusion in the MIL-HDBK-5. Materials included in this report are standardized with regard to composition and processing methods and are described by industry, government, or company specifications. |
|
| Precision Hinge Mounting Stops |
14 JUN 1999 |
10 pages |
| Authors:
William H. Nedderman Jr; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| The present invention relates to a precision hinge apparatus. To accurately and reproducibly set the angle of a hinge, especially a very small hinge, a precision hinge and angled mounting stops are provided. The device comprises a hinge joint having a fastener, such as a screw, connecting two bodies. A flat C-shaped mounting stop fits over the fastener and has two straight outer edges that contact each of the two ... |
|
| Method and Apparatus for Inducing Fully-Reversed Three-Dimensional Loading on a Non-Rotating Beam. |
16 FEB 1999 |
|
| Authors:
Michael A. Troffer; William M. Appleman; Joseph F. Korczynski Jr; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| The inventive fatigue-testing apparatus features a compact orbital mechanism which rotates a bending force around a non-rotating test section and a stationary test bed. In addition to applying a bending force, some inventive embodiments apply an axial force and a torsional force, thereby accomplishing full-scale evaluation of test sections under three-dimensional loading; the inventive practice for applying bending, torsional and axial loads compares favorably with conventional practice in terms of ... |
|
| Spline Variational Theory for Composite Bolted Joints |
JAN 1999 |
52 pages |
| Authors:
E. Iarve; DAYTON UNIV OH RESEARCH INST
|
| The hybrid numerical approximation model for predicting stresses and strains in open-hole composites was refined. The model was also expanded to include singular full-field stress analysis of multi-interface composites under mechanical, thermal and bearing loads. The rigid fastener hole problem was also examined. This hybrid model, using spline variational theory and Reissner's variational principle, provides accurate solutions in the vicinity of the singularity. Convergence with coarse subdivisions was observed if ... |
|
| Advanced Pavement Design: Finite Element Modeling for Rigid Pavement Joints, Report II: Model Development |
MAR 98 |
180 pages |
| Authors:
Michael J. Hammons; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS
|
| The contribution of a cement-stabilized base course to the strength of the rigid pavement structure is poorly understood. The objective of this research was to obtain data on the response of the ng'id pavement slab-joint- foundation system by conducting laboratory-scale experiments on jointed rigid pavement models and to develop a comprehensive three-dimensional (3D) finite element model of the rigid pavement slabjoint4oundation system that can be implemented in the advanced pavement ... |
|
| The National Shipbuilding Research Program, Development and Evaluation of Improved Flux-Cored Welding Consumables, Phase 1 |
09 JAN 1998 |
36 pages |
| Authors:
NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| The objective of NSRP Project #7-95-4 is to evaluate and develop an improved flux-cored wire for use in commercial shipbuilding that can be produced within the U.S. and is comparable or exceeds those available from foreign producers. This report deals with a portion of the first phase consisting of evaluating FCAW wires from U.S. and foreign manufacturers to identify the differences in weldability, arc characteristics and quality. The electrode evaluation ... |
|
| Ground-Fault Protection on Construction Sites |
1998 |
33 pages |
| Authors:
DEPARTMENT OF LABOR WASHINGTON DC OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION
|
| With the wide use of portable tools on construction sites, the use of flexible cords often becomes necessary. Hazards are created when cords, cord connectors, receptacles, and cord and plug-connected equipment are improperly used and maintained. Generally, flexible cords are more vulnerable to damage than is fixed wiring. Flexible cords must be connected to devices and to fittings so as to prevent tension at joints and terminal screws. Because a ... |
|
| Exploiting Natural Dynamics in Robot Control |
1998 |
|
| Authors:
Matthew M. Williamson; MASSACHUSETTS INST OF TECH CAMBRIDGE
|
| This paper presents an approach to robot arm control based on exploiting the dynamical properties of an adaptive oscillator circuit coupled to the joints of an arm. The approach is implemented on a real robot arm, and swings pendulums at their natural frequencies, turns cranks and manipulates slinky toys. These actions are all achieved using the same architecture, without any modeling of the arm or its environment. The simple nature ... |
|
| Investigation of Corrosion on Inland Petroleum Distribution System Aluminum Pipe Grooved Ends Caused by Rubber Gaskets |
AUG 97 |
31 pages |
| Authors:
Howard E. Horner; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| Because of fuel leaks at a number of mechanically connected joints, the Inland Petroleum Distribution System (IPDS) unit at Fort Lee, VA, was disassembled. Corrosion had occurred on the bare surfaces of the aluminum pipe single-grooved ends in the connection joints. These corroded surfaces were in contact with the rubber gaskets inside the IPDS joint couplings. An investigation was performed to determine the cause of the corrosion. The joint gasket ... |
|
| Composite Failure Analysis Handbook Update 1 |
AUG 97 |
264 pages |
| Authors:
Gregory M. Walker; BOEING DEFENSE AND SPACE GROUP SEATTLE WA MATERIALS PROCESSES AND PHYSICS TE CHNOLOGY DIV
|
| This report supplements the data and analyses provided in the previously released 'Composite Failure Analysis Handbook,' WL-TR-91-4032/DOT/ FAA/CT-91/23. It contains fractograhic data from failed composite test specimens as well as ease histories of failed composite structure. Fractographic data from statically loaded test specimens are presented for carbon/epoxy (AS4/3501-6), carbon/ pseudothermoplastic (AS4/KIII), carbon/polyimide (AS4/PMR-15), carbon/ thermoplastic (AS4/PEEK), carbon/bismaleimide (AS4/MR-54-4), and carbon and glass low-temperature curing epoxy, (HTA 5131-12K/Rutapox L-20/SL and EC ... |
|
| Modeling Body Joint Loads during Equipment Decontamination Operations |
JUL 1997 |
99 pages |
| Authors:
R. W. McMahon; T. Shams; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD HUMAN RESEARCH AND ENGINEERING DIRECTORATE
|
| The General Engineering and Systems Analysis Company (GESAC), Inc., under contract with the Human Research and Engineering Directorate of the U.S. Army Research Laboratory (ARL), (contract number DAAL01-94-P-0906) estimated body joint loading using a computer simulation program called DYNAMAN(copyright) . This work was performed in support of the U.S. Army Chemical and Biological Defense Command (CBDCOM) modular decontamination system (MDS) development program. The objective of this effort was to model ... |
|
| Instantaneous Axis of Rotation for Continuous Human Knee Motion |
JUN 97 |
128 pages |
| Authors:
Steven Parks; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Previous studies of human knee motion are based on finite rotation data collected using large rotation steps varying from 5 to 30 degrees. In some cases this rotation data is used to develop axes of rotation for the joint. For such analysis, the rotation axis developed may be significantly different from the joint's instantaneous axis of rotation because, in general, the axis of rotation developed using finite rotation steps only ... |
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| The Analysis and Design of Tee-Joints for Composite Hull Structures |
JUN 1997 |
117 pages |
| Authors:
jack Bish; Keith T. Kedward; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD SURVIVABILITY STRUCTURES AND MATERIALS DIRECTORATE
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| The design of polymer matrix composite joints is strongly influenced by the presence of out-of-plane or through-the-thickness stresses. These stresses can be critical, since out-of-plane interlaminar tension and shear strengths, as well as moduli, are strongly influenced by the low strength and stiffness of the polymer matrix constituents, as well as the fiber matrix interface. To aid in the design of these structures, this research develops a methodology for predicting ... |
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