| Nonlinear Structural Health Monitoring of the Responsive Space Satellite Systems Using Magneto Elastic Active Sensors (MEAS) |
30 Nov 2011 |
74 pages |
| Authors:
Andrei Zagrai; Timothy Barnes; Davit Kukhalashvili; Rakhim Aitbaev; David Conrad; NEW MEXICO INST OF MINING AND TECHNOLOGY SOCORRO
|
 | The project explores application of magneto-elastic active sensors (MEAS) for structural health monitoring (SHM) of responsive space satellite systems. Design, development and fabrication procedures for MEAS are presented and associated electrical and mechanical characteristics are discussed. MEAS miniaturization efforts are highlighted. Examples of MEAS-enabled SHM testing in aerospace structures of simple and complex geometry, such a honeycomb and realistic satellite panels, are provided. Nonlinear SHM methodologies using MEAS are considered ... |
|
| Role of NDI in ABDR Assessment, Equipment & Logistics |
May 2010 |
22 pages |
| Authors:
Ferdinando Dolce; ITALIAN AIR FORCE FLIGHT TEST CENTRE ROME ITALY
|
| Use of Non Destructive Testing (NDT) technique during aircraft maintenance operations is increasing in the last years as well as the tools to perform these inspections are widening their field of application. Damage tolerance design approach has been selected by aeronautic industry for the last years also thanking to the most modern NDT capabilities, like ultrasound and thermography, which have been showing more and more reliable results. Whenever a safe ... |
|
| Fuel Economy and Mobility of Multi-Wheel Drive Vehicles: Modeling and Optimization Technology |
Jan-2009 |
9 pages |
| Authors:
Vladimir V Vantsevich; Jeremy P Gray; LAWRENCE TECHNOLOGICAL UNIV SOUTHFIELD MI
|
| A distinctive feature of unmanned and conventional terrain vehicles with four or more driving wheels consists of the fact that energy/fuel efficiency and mobility depend markedly not only on the total power applied to all the driving wheels, but also on the distribution of the total power among the wheels. As shown, under given terrain conditions, the same vehicle with a constant total power at all the driving wheels, but ... |
|
| NUWC XP-1 Polyurethane-Urea: A New, Acoustically Transparent Encapsulant for Underwater Transducers and Hydrophones |
01-Sep-2003 |
5 pages |
| Authors:
Thomas Ramotowski; Kirk Jenne; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
|
| Almost all acoustic projectors and hydrophones are encapsulated in polymeric materials. These coatings protect the underlying sensors and electronics from physical damage and water ingression, while allowing the passage of acoustical energy without significant reflection, loss, or distortion. Critical material parameters for superior acoustical performance include: (1) density and sound speeds close to those of seawater; (2) low mechanical loss tangent; (3) medium to high shear loss tangent; (4) low ... |
|
| Active and Reactive Shells |
14 AUG 2002 |
9 pages |
| Authors:
Amr M. Baz; MARYLAND UNIV COLLEGE PARK DEPT OF MECHANICAL ENGINEERING
|
| Active Shells (AS) and Reactive Shells (RS) are proposed to attenuate the undesirable wave propagation developed by various sources of external excitations. Emphasis will be placed here on excitations resulting from moving ballistic pressures that are developed during the firing of projectiles in gun barrels. The proposed shells are envisioned to be made of tubes that have passive or active sources of mechanical impedance mismatch which are placed along their ... |
|
| Effect of Isokinetic Strength Training and Deconditioning on Bone Stiffness, Bone Mineral Density and Bone Turnover in Military-Aged Women |
JUN 2002 |
|
| Authors:
William G. Herbert; Sharon M. Nickols-Richardson; Lawrence H. Cross; Warren K. Ramp; David F. Wooten; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG
|
 | For physically active military personnel, stress fractures are debilitating and costly. Female soldiers sustain twice the number of stress fractures compared to males. Exercise interventions for women are needed to promote military readiness in ways that enhance bone strength and reduce stress fractures. This study, currently in progress, is investigating the effects of 30 weeks of concentric Vs eccentric isokinetic resistance training on bone stiffness (mechanical impedance), bone quality (mineral ... |
|
| Sixth Phantom Users Group Conference |
JAN 2002 |
141 pages |
| Authors:
Karl D. Reinig; COLORADO UNIV AT FITZSIMMONS AURORA HEALTH SCIENCES CENTER
|
| This grant represented the major funding for the Sixth PHANToM Users Group Conference. The conference was held in a workshop style at the Given Institute in Aspen Colorado. This was the second time that the University of Colorado hosted the conference. The conference successfully attracted haptic researchers from around the world In addition to the individual papers, the conference included a discussion of haptic standards and multiple tutorials. |
|
| Effect of Isokinetic Strength Training and Deconditioning on Bone Stiffness, Bone Density and Bone Turnover in Military-Aged Women |
JUN 2001 |
48 pages |
| Authors:
William Herbert; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG
|
| For physically active military personnel, stress fractures are debilitating and costly. Female soldiers sustain twice the number of stress fractures compared to males. Exercise interventions for women are needed to promote military readiness in ways that enhance bone strength and reduce stress fractures. This study, currently in progress, is investigating the effects of 30 weeks of concentric Vs eccentric isokinetic resistance training on bone stiffness (mechanical impedance), quality (mineral density ... |
|
| Electro-Mechanical Modeling of the Dynamics of Active Control Systems Based on an Impedance Approach |
MAR 96 |
111 pages |
| Authors:
Frederic Lalande; Craig A. Rogers; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG CENTER FOR INTELLIGENT MA TERIAL SYSTEMS AND STRUCTURES
|
| In this fundamental research program, the focus was to develop an understanding of the physics of actively controlled material systems, especially the power consumption and energy transfer mechanisms. A new impedance approach was further developed, giving particular attention to applications involving structures with impedance characteristics similar to aircraft structures. This newly developed impedance approach has an advantage over conventional approaches, such as the quasi-static and equivalent thermal force approaches, in ... |
|
| Nondestructive Evaluation of Electrodeposited Chromium |
NOV 92 |
16 pages |
| Authors:
Mark E. Todaro; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS
|
| Benet Laboratories is pursuing methods for nondestructively evaluating the quality and adhesion of electrodeposited chromium coatings on the bore of large caliber gun tubes. The Army currently has no suitable means for testing such coatings nondestructively. A poor quality or poorly adherent coating shows up only when several test rounds are fired through the tube, removing portions of the coating and exposing the steel underneath. Recent in- house work has ... |
|
| Passive Vibration Damping |
JAN 91 |
|
| Authors:
S. K. Kurtz; Shoko Yoshikawa; PENNSYLVANIA STATE UNIV UNIVERSITY PARK MATERIALS RESEARCH LAB
|
| Several attempts have been made to make vibration dampers using piezoelectric damping effect. Among PZT ceramic samples made in the course of this research, PZT stack sample with optimally tuned external resistor gave a maximum mechanical loss of 0.25 and elastic modulus of 70 to 90 GPa measured using an electrical resonance technique. In order to utilize piezoelectric damping effect for structural materials, PZT with polymer or metal matrix have ... |
|
| Seismic Response to Sonic Boom-Coupled Rayleigh Waves |
28 JUN 90 |
261 pages |
| Authors:
Mark R. Legg; Jerold M. Haber; BBN SYSTEMS AND TECHNOLOGIES CORP CANOGA PARK CA
|
| Whenever sonic booms strike the ground a certain amount of energy is transferred to the ground which propagates as seismic waves. Under most conditions, the energy transfer is very inefficient, and the seismic wave energy is dissipated over a relatively short distance. If, however, a supersonic aircraft flew in a manner so that the sonic boom carpet velocity matched the propagation velocity of seismic surface waves (Rayleigh waves), the magnitude ... |
|
| Force Determination Sensitivities Study for Full-Scale Helicopter Ground Vibration Testing |
SEP 89 |
63 pages |
| Authors:
Nick Calapodas; Keith Hoff; ARMY AVIATION RESEARCH AND TECHNOLOGY ACTIVITY FORT EUSTIS VA AVIATION APPLI ED TECHNOLOGY DIRECTORATE
|
| A fundamental objective of the Army's research and development efforts is to increase the reliability of the Army's airmobility force, which consists primarily of rotary-wing aircraft. Excessive vibrations have always been a problem for helicopters due to the vibratory airloads generated by the main rotor as it moves edgewise through the air. Maintenance and part replacement costs require that potential vibration problems be diagnosed as early as possible in the ... |
|
| Shock and Vibration Symposium (59th) Held in Albuquerque, New Mexico on 18-20 October 1988. Volume 1 |
OCT 88 |
387 pages |
| Authors:
SANDIA NATIONAL LABS ALBUQUERQUE NM
|
| Partial contents: The Quest for Omega = sq root(K/M) -- Notes on the development of vibration analysis; An overview of Statistical Energy analysis; Its development and engineering applications; Data bases -- GREEDI -- The computerization of the DOE/DOD environmental data bank; A shock and vibration databases for military equipment and for aircraft; Virbroacoustic payload environment prediction system (VAPEPS) -- The importance of non-resonant and inplane vibration transmission in statistical energy ... |
|
| The Modeling of Viscoelastic Circular Plates for Use as Waveguide Absorbers |
SEP 88 |
211 pages |
| Authors:
Charles D. Hettema; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The need exists to reduce structural vibrations in plates, such as ship's hulls. It was proposed to use waveguide absorbers as a means to reduce structural vibrations. A waveguide absorber is a device which is made from damping material but mounted to the structure at a point rather than the full surface. A waveguide absorber removes and then dissipates vibrational energy from the structure through traveling waves. The performance of ... |
|
| Prediction of Crack Growth in Aqueous Environments |
JUL 86 |
113 pages |
| Authors:
L. E. Eiselstein; M. C. McKubre; R. D. Caligiuri; SRI INTERNATIONAL MENLO PARK CA
|
| The report describes the results of a research program to simultaneously determine the mechanical and electrochemical process that occur within and near the tip of active stress corrosion and corrosion-fatigue cracks. Electrochemical/mechanical impedance analysis is one of the few techniques with this capability. Our approach was to make electrochemical/mechanical impedance measurements on HY80 steel in 3.5 wt% NaCl solutions under corrosion-fatigue conditions. The data were then analyzed by means of ... |
|
| Nondestructive Tests for the Evaluation of Railroad Track Foundations and Lime Slurry Pressure Injection Stabilization |
MAR 85 |
|
| Authors:
R. H. Ledbetter; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS GEOTECHNICAL LAB
|
| This report presents the results of a field evaluation of nondestructive test techniques that could be used for assessing the overall condition of a track support system and for determining the improvement in foundation support derived from lime slurry pressure injection. A number of test techniques were evaluated on an artificial railroad embankment and level area at the US Army Engineer Waterway Experiment Stations, Vicksburg, MS, and on two test ... |
|
| Symposium on Flow-Induced Vibrations Held in New Orleans, Louisiana on 9-14 December 1984. Volume 5. Turbulence-Induced Noise and Vibration of Rigid and Compliant Surfaces |
14 DEC 84 |
106 pages |
| Authors:
M. P. Paidoussis; A. J. Kalinowski; AMERICAN SOCIETY OF MECHANICAL ENGINEERS NEW YORK
|
| Contents: A Noncontacting Electrooptic Displacement Sensor for Piezoelectrically Driven Active Surfaces; An Optical Technique for Measuring the Flow Induced Motion of a Compliant Surface; Practical Requirements of Turbulent Boundary Layer Forcing Function Measurements With Wave Vector Filters; An Innovative Fast Fourier Transform Array Technique for Low Wave Number Measurements of the Turbulent Boundary Layer Fluctuating Pressure Field; Use of Random Forces to Simulate the Vibroacoustic Response of a Plate Excited ... |
|
| A Treatise on Acoustic Radiation. Volume 2. Acoustic Transducers |
1983 |
518 pages |
| Authors:
S. Hanish; NAVAL RESEARCH LAB WASHINGTON DC
|
| This book is a second volume of the author's series on Acoustic Radiation. The first two chapters review standard theory of equivalent circuits, with a substantial introduction to bond-graph theory as applied to transducers. Chapters 3-8 and 10 discuss special topics in current acoustic transducer practice. Chapter 9 is devoted to basic generalizations which relate acoustic transducer mechanical impedances to acoustic radiation. (Author) |
|
| In-Flight Hydrophone Deployment System for Underwater Vehicles. |
14 SEP 1982 |
|
| Authors:
Orrin W. Albert Jr; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| A hydrophone deployment apparatus is provided for an underwater vehicle wherein the apparatus includes an annular drum releasably mounted about the tail portion of the vehicle. A plurality of arms are pivotally connected to the aft portion of the drum and are capable of swinging from forward positions flush with the vehicle to aft positions behind the drum. A device is provided for enabling retention and selective releasing of the ... |
|
| Localized Impact Damage in Ceramics |
31 AUG 1982 |
|
| Authors:
H. P. Kirchner; D. M. Richard; T. J. Larchuk; J. A. Tiracorda; J. A. Ragosta; CERAMIC FINISHING CO STATE COLLEGE PA
|
| The following topics are covered in this report: Contact Damage in Hot Pressed and CVD Zinc Sulfide, Comparisons of Static and Impact Loading Damage in Zinc Sulfide, Load-Radial Crack Length Relations for Spherical Indentations in Hot Pressed ZnS, Elastic Recovery at Static Loading and Impact Indentations in MgF2, and Effect of Mechanical Impedance Ratio on the Distribution of Stress Wave Energy During Particle Impact. |
|
| A Hybrid Fem-T-Matrix Technique for the Analysis of Acoustic Wave Scattering by Elastic Shells of Revolution |
1982 |
|
| Authors:
Kumar Eswaran; Vijay K. Varadan; Vasundara V. Varadan; OHIO STATE UNIV COLUMBUS DEPT OF ENGINEERING MECHANICS
|
| A hybrid finite element cum T-matrix technique is introduced for the analysis of problems involving acoustic wave scattering by shells of revolution immersed in water. The concept of a mechanical impedance or receptance is used from the theory of vibrations to provide a relationship between the velocity of the shell surface and the pressure acting upon it. This relationship is introduced in the Helmholtz integral relations for the incident and ... |
|
| Structural System Identification Technology Verification |
NOV 1981 |
218 pages |
| Authors:
N. Giansante; A. Berman; W. G. Flannelly; E. J. Nagy; KAMAN AEROSPACE CORP BLOOMFIELD CT
|
| Structural system identification is the method of obtaining structural and dynamic mathematical models and improving existing mathematical models using ground vibration test data. The purpose of the subject program was to perform experimental, development, and research work to verify the concepts of structural system identification technology. To accomplish this, system identification techniques were applied to a U. S. Army AH-1G helicopter fuselage to create a mathematical model from ground vibration ... |
|
| Research to Provide a Theoretical Determination of Surface Acoustic Wave Velocity and Impedance Differences between Metal Strips and Free Surface Regions of Metallic Gratings |
JUL 1981 |
|
| Authors:
B. J. Hunsinger; ILLINOIS UNIV AT URBANA COORDINATED SCIENCE LAB
|
| With the advent of surface acoustic wave resonators and withdrawal weighted filters, quantitative knowledge of the velocity and acoustic impedance differences between metal strips and free surface regions in metallic gratings used for these structures has become necessary. During the course of this program mass loading, topographical effects, electrical loading, and energy storage have been considered and the surface acoustic wave velocity and impedance differences (DELTERV and DELTERZ) have been ... |
|
| Mechanical Impedance of the Human Outer Ear. (Mechanische Impedanzen am Aeusseren OHR des Menschen) |
FEB 1981 |
|
| Authors:
H. Els; J. Schroeter; ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)
|
|
| Research to Provide a Theoretical Determination of Surface Acoustic Wave Velocity and Impedance Differences between Metal Strips and Free Surface Regions of Metallic Gratings. |
FEB 1981 |
|
| Authors:
B. J. Hunsinger; S. Datta; ILLINOIS UNIV AT URBANA COORDINATED SCIENCE LAB
|
| This interim report describes the scattering theory approach for calculating the shift in velocity and acoustic reflection caused by one electrode (which can be buried) in an infinite array. Piezoelectric loading as well as first and second order mechanical loading are considered. The results calculated from electrode geometry and material constants are presented in the form of scatter matrices from which transmission line model parameters are derived. The analysis is ... |
|
| Compressional Damping in Three-Layer Beams Incorporating Nearly Incompressible Viscoelastic Cores. |
OCT 1980 |
|
| Authors:
Bruce Edward Douglas; DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER ANNAPOLIS MD PROPULSION AND AUXILIARY SYSTEMS DEPT
|
| The transverse free mechanical impedance response of an elastic-viscoelastic-elastic beam incorporating the compressional damping mechanism is considered. The work of Douglas and Yang is extended to include shear deformation and rotary inertia in the elastic layers. The effects of nearly incompressible viscoelastic damping cores on the compressional frequency, and hence on the spectral range of damping effectiveness for the composite, is also discussed. Results of the analysis are shown to ... |
|
| The Shock and Vibration Bulletin. Part 2. Measurement Techniques and Data Analysis, Dynamic Measurements, Vibration and Acoustics |
SEP 80 |
263 pages |
| Authors:
NAVAL RESEARCH LAB WASHINGTON DC SHOCK AND VIBRATION INFORMATION CENTER
|
| Partial Contents: Precision inertial angular vibration measuring system; Angular acceleration measurement errors induced by linear accelerometer cross-axis coupling; Method for experimentally determining rotational mobilities of structures; Transient effects in acoustic sound reduction measurements; Shock measurements; Shock measurement during ballistic impact into armored vehicles; Automatic data channel calibration and noise identification; Statistical estimation of simulated yield And overpressure; Assessment of the common carrier shipping environment; Shock And vibration environment in a ... |
|
| Vibration of a Clamped Circular Plate Driven by a Noncentral Force. |
31 OCT 1979 |
|
| Authors:
J. C. Snowdon; PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
|
| Expressions are stated for the transmissibility and for the driving-point impedance of an internally damped circular plate of radius a with a clamped boundary that is driven by a vibratory point force at an arbitrary distance micron from the plate center. Expressions are also stated for the plate transmissibility when the plate is loaded at the arbitrary driving point either by a lumped mass, by a dynamic vibration absorber--or, simultaneously, ... |
|
| The Shock and Vibration Bulletin. Part 2. Modal and Impedance Analysis, Human Response to Vibration and Shock, Isolation and Damping, Dynamic Analysis |
SEP 1979 |
217 pages |
| Authors:
NAVAL RESEARCH LAB WASHINGTON DC SHOCKAND VIBRATION INFORMATION CENTER
|
| Contents: An Impedance Technique for Determining Low Frequency Environments; A Statistical Look at Modal Displacement Response to Sequential Excitations; On Determining the Number of Dominant Modes in Sinusoidal Structural Response; Lateral and Tilt Whirl Modes of Flexibly Mounted Flywheel Systems; Whole-Body Vibration of Heavy Equipment Operators; Research Related to the Expansion and Improvement of Human Vibration Exposure Criteria; Computer Aided Design of Passive Vibration Isolators for Airborne Electro-Optical Systems; Design ... |
|
| Handbook of Vibration and Noise Control. |
27 APR 1979 |
|
| Authors:
J. C. Snowdon; PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
|
| The static and dynamic properties of rubberlike materials are reviewed initially, followed by discussion of the simple and compound mounting systems. Reference is also made to the dynamic vibration absorber and to the measurement of mount transmissibility. Three sections then describe the natural frequencies, the mechanical impedances, and the transmissibility of structural members. Finally, four-pole parameter analyses are reviewed and the relative transmissibility of various mounting systems supported by a ... |
|
| Structure-Borne Noise and Sound Radiation Associated with a Point Driven Grid Supported Infinite Plate. |
FEB 1979 |
|
| Authors:
W. T. Ellison ; j. m. garrelick; CAMBRIDGE ACOUSTICAL ASSOCIATES INC MA
|
| A general solution has been developed for the transform responses and the radiated pressure associated with a fluid loaded, orthogonal grid supported plate driven by a harmonic point force. For the case of light or no fluid loading the solution is in a closed form. A particular interest in developing this solution was to determine the structural pass-band characteristics of such a structure in terms of the inertial and elastic ... |
|
| Dynamic Response of Lift Fans Subject to Varying Backpressure. |
JUL 1978 |
|
| Authors:
John M. Durkin; Lawrence H. Luehr; DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER BETHESDA MD AVIATION AND SURFACE EFFECTS DEPT
|
| An analytical investigation of the dynamic performance of a centrifugal lift fan was conducted to provide an explanation for the behavior which occurred when the fan was subjected to a varying backpressure. Analysis of test data shows that the fan response del Q/del P can be represented by a first-order lag system. An in-depth analysis of the various elements of the lift fan system revealed that the inertia of the ... |
|
| Transient Response of Structures by Use of Component Modes. |
FEB 1978 |
|
| Authors:
J. M. Klosner; D. Ranlet; WEIDLINGER ASSOCIATES NEW YORK
|
| A general method is presented for obtaining the dynamic equations of an elastic structure to which elastic and/or nonlinear substructural elements are attached. (Author) |
|
| Study of Vibration in Concrete, Report 3. Mechanics of Motion of Fresh Concrete. |
SEP 1977 |
|
| Authors:
A. Michel Alexander; ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS
|
| Mechanical impedance tests on fresh concrete revealed the properties that resist motion. It was found that there were two distinct mechanical impedance curves depending on whether the dynamic stress applied was above or below a threshold level. At low stress levels, the impedance of the mixture was almost flat, possessing high damping, stiffness, and mass characteristics. No resonant frequency was found, but on the contrary, a wide spectrum of frequencies ... |
|
| Development of Advanced Concepts for Noise Reduction in Tracked Vehicles |
AUG 1977 |
82 pages |
| Authors:
Thomas R. Norris; Ronald B. Hare; Anthony G. Galaitsis; Georges R. Garinther; FMC CORP SAN JOSE CA ORDNANCE ENGINEERING DIV
|
| This investigation develops an understanding of the noise sources, the acoustical and vibratory paths through which energy enters the hull structure, and the mechanism by which noise arrives at personnel locations. A theoretical and experimental analysis of primary noise source of the vehicle, i. e. the track and suspension system, consisted of three phases: (1) The design of a computer program to simulate the track and suspension; (2) The isolation ... |
|
| Numerical Simulation of Forced Vibration Tests on a Buried Arch. |
01 MAR 1977 |
|
| Authors:
J. Isenberg; H. S. Levine; S. H. Pang; WEIDLINGER ASSOCIATES MENLO PARK CALIF
|
| Finite element simulation of a buried arch structure shows that the effective damping depends on backfill conditions. This information is used to explain the occurrence of resonance in forced vibration tests of buried rectangular structures and its absence in tests of the arch. Implications of the findings for developing single degree of freedom models of complex structures are examined. (Author) |
|
| Space Shuttle Response to Acoustic Combustion Instability in the solid Rocket Boosters. |
JUN 1976 |
|
| Authors:
F. R. Jensen; HERCULES INC MAGNA UTAH BACCHUS WORKS
|
| Response of the Space Shuttle vehicle to unstable acoustic pressure oscillations in the solid rocket boosters (SRB's) was calculated. The response was expressed in terms of forces and displacements at the attach points between the SRB's and the External Tank (ET), and between the ET and the Orbiter. The response calculations satisfied the objectives of the program. The NASTRAN computer program was used to analyze the various finite element shuttle ... |
|
| Electroacoustic Modeling of Magnetostrictive Shells and Rings. Part 2. EIGSHIP Predicted Performance; Experimental Measurements; and Computer Listing of EIGSHIP. |
19 APR 1976 |
|
| Authors:
S. Hanish; B. J. King; R. V. Baier; P. H. Rogers; NAVAL RESEARCH LAB WASHINGTON D C
|
| The mathematical model of the electroacoustic performance of a force-driven free-flooding magnetostrictive cylinder shell used as an underwater sound transducer, originally developed in another report, has been coded into a computer program called EIGSHIP. This program is designed to predict electrical and mechanical impedances of the loaded shell, transmitting responses, electroacoustic efficiency, surface velocities, far-field beam patterns, and other relevant performance parameters. An experimental check on the prediction capabilities of ... |
|
| Analytical Prediction of Motor Component Vibrations Driven by Acoustic Combustion Instability |
FEB 1976 |
643 pages |
| Authors:
F. R. Jensen; HERCULES INC WILMINGTON DE SYSTEMS GROUP
|
| A detailed investigation has been conducted on the structural dynamic response of solid rocket motors. The study was particularly concerned with estimating the structural response to unstable acoustic combustion oscillations that often occur in solid motors during motor firing time. Detailed finite element analyses were performed on the Poseidon C-3 second stage motor and on the Minuteman III third stage motor using a NASTRAN computer program. In addition, the response ... |
|
| Vibration Measurements on the Rotor Shaft of the UH-1M Helicopter. |
FEB 1976 |
|
| Authors:
Harvey I. Goldman; FRANKFORD ARSENAL PHILADELPHIA PA
|
| This report describes a program of in-flight vibration measurements carried out on a platform mounted atop the rotor mast on the UH-1M helicopter. Results of a real time analysis of the data are presented which reveal that a low level of vibration exists at that site making it a good location for the future placement of fire control instrumentation. A mechanical impedance study is also presented which shows that much ... |
|
| The Shock and Vibration Bulletin. Part 5. Isolation, Damping, Dynamic Analysis |
JUN 1975 |
208 pages |
| Authors:
NAVAL RESEARCH LAB WASHINGTON DC SHOCK AND VIBRATION INFORMATION CENTER
|
| Contents: Impact on Complex Mechanical Structures; Energy Absorption and Phase Effects in Shock Excited Coupled Systems; High Performance Vibration Isolation System for the DD963 Gears; The Design and Measurement of a High Impedance Foundation to 20 kHz and Use of the Data in Correcting Noise Measurements; Response of Thick Structures Damped by Viscoelastic Material with Application to Layered Beams and Plates; Controlling the Dynamic Response of Jet Engine Components; An ... |
|
| The Shock and Vibration Bulletin. Part 2. Invited Papers, Structural Dynamics. |
AUG 1974 |
211 pages |
| Authors:
NAVAL RESEARCH LAB WASHINGTON D C SHOCK AND VIBRATION INFORMATION CENTER
|
| The report is a compilation of papers relative to structural and dynamic response of structures exposed to shock and vibration environments. |
|
| Operator's Manual. DUMILOAD Transducer Tester. |
AUG 1974 |
|
| Authors:
Wayne A. Miller; GENERAL ELECTRIC CO SYRACUSE N Y TRANSDUCER PRODUCTS OPERATION
|
| A DUMILOAD (DUmmy Mechanical Impedance LOAD) testing device has been developed to allow the rapid testing of sonar transducer elements. The operator's manual is a description of the installation, operation, and maintenance of the device for high power testing transducers. |
|
| Performance Specification for DUMILOAD Transducer Tester. |
AUG 1974 |
|
| Authors:
Wayne A. Miller; GENERAL ELECTRIC CO SYRACUSE N Y TRANSDUCER PRODUCTS OPERATION
|
| A DUMILOAD (DUmmy Mechanical Impedance LOAD) testing device has been developed to allow the rapid testing of sonar transducer elements. Significant features of the device described in this performance specification are its high power operation, nondestructive connect/disconnect technique, and rapid operation. |
|
| The Shock and Vibration Bulletin. Part 1. Summaries of Presented Papers. |
OCT 1973 |
112 pages |
| Authors:
NAVAL RESEARCH LAB WASHINGTON D C SHOCK AND VIBRATION INFORMATION CENTER
|
| The report is a compilation of summaries of papers relative to shock and vibration phenomena in various environments and structures. Methods of isolation and damping are suggested. |
|
| Circular Footings on Viscoelastic Foundations. |
SEP 1973 |
|
| Authors:
T. M. Lee; COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER N H
|
| The interaction of a vibrating circular footing with its foundation was investigated. To account for the energy dissipation when propagating through the supporting ground, the foundation was assumed to behave as a viscoelastic medium. The response of the footing was found to depend upon its own mass and vibration frequencies and the foundation material properties. But, for the convenience of engineering applications, the response was expressed in terms of a ... |
|
| Development of Mechanical Impedance Techniques to Analyze Weapon Mount Interfaces. |
JUN 1972 |
|
| Authors:
Robert J. Radkiewicz; ARMY WEAPONS COMMAND ROCK ISLAND ILL WEAPONS LAB
|
| A technique for determining the impedance of weapon mounts is being developed by personnel of the Research Directorate, Weapons Laboratory at Rock Island. This technique involves the use of the firing pulse of the weapon. Results of the study have indicated that the firing pulse may induce frequencies of which the maximum one could be ten times greater than the dominant resonant frequency of the system. Programs to acquire and ... |
|
| The Shock and Vibration Bulletin. Part I. Invited Papers, Specifications, Mechanical Impedance, Transportation and Packaging. |
JAN 1972 |
252 pages |
| Authors:
SHOCK AND VIBRATION INFORMATION CENTER (DEFENSE) WASHINGTON D C
|
| The report contains papers presented at a symposia relative to shock, vibration, ground motion, and describes methods of measurement and suggested methods for suppression. |
|
| Dynamic Response Characteristics of the Human Vertebral Column. |
1972 |
|
| Authors:
Leon Kazarian; KAROLINSKA INST STOCKHOLM (SWEDEN)
|
| Contents: Theory of Impedance; Review of Literature; Experimental Methods; Observations and Experiments -- The Response of the vertebral unit to constant compressive loading, The dynamic response of the unconditioned and conditioned vertebral segment, The impedance responses of the unconditioned intervertebral disk, Creep responses at various vertebral levels, Effect of the posterior arch on the anterior spinal column; General Observations, Discussions and Conclusions Resulting from Experiments; and Studies on the Impedance ... |
|
Reports by Keyword(s)
MECHANICAL IMPEDANCE
