| Some Strip Contributions to Transducer Design and Analysis |
95 |
196 pages |
| Authors:
David L. Carson; Alan K. Walden; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
 | Transducer Reliability Improvement Program. such as the Simplified Guidance Mode for k sub 33 mode transducer elements. The model's usefulness in understanding and explaining certain transducer design techniques for a 33-node projector element and array is discussed. The model Is augmented and applied such that it may be used 1) as en educational tool to help inexperienced transducer design engineers acquire some subject knowledge. skills and insight; and 2) to ... |
|
| Temperature Dependence of the Electromechanical Properties of O-3 PbTiO3-Polymer Piezoelectric Composite Materials |
JUL 1994 |
13 pages |
| Authors:
Kurt M. Rittenmyer; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The electromechanical properties of 0-3 ceramic-polymer composite piezoelectric materials manufactured by NTK Corporation in Japan have been measured as a function of temperature using several techniques. The elastic, dielectric, and piezoelectric constants were measured by fitting the complex admittance vs frequency spectrum to a model of a piezoelectric resonator near the electromechanical resonance. These properties are shown to vary significantly with temperature as a result of the glass-transition region of ... |
|
| Direct Measurements of Edge Diffraction from Soft Underwater Acoustic Panels |
JUN 1994 |
12 pages |
| Authors:
Jean C. Piquette; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Direct measurements of edge diffraction arising from the interaction of an acoustic wave with an underwater panel that satisfies soft-body boundary conditions are reported. The measurements were obtained by utilizing a specially fabricated 'airbox' sample, which is literally a box of air, fabricated using thin polycarbonate walls. The airbox theoretically would exhibit a typical insertion loss in excess of 60 dB (in the absence of edge diffraction), thus avoiding interference ... |
|
| A New Concept of a Low-Frequency Underwater Sound Source |
APR 1994 |
7 pages |
| Authors:
D. M. Donskoy; J. E. Blue; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| A new concept of a low-frequency (< 1000-Hz) underwater sound source has been developed and tested. The oscillation of a rigid body and a means for converting the dipole oscillation of the body to monopole radiation are used in this source.. The source can be powered with electric or linear motors or hydrodynamic exciters that convert tow or flow to vibration. To prove the concept, a small version of the ... |
|
| Electrostrictive Ceramics for Underwater Transducer Applications |
FEB 1994 |
10 pages |
| Authors:
Kurt M. Rittenmyer; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The electromechanical properties of two electrostrictive materials designed for use in underwater acoustic applications are determined as functions of temperature and electric field. The materials are 0.859Pb(Mgl/3Nb2/3)O3-0 . 141 PbTiO3 doped with 2.5% SrTiO3 or BaTiO3. Dielectric properties are determined as functions of temperature and electric field. The equivalent piezoelectric coefficients were found as functions of temperature to be equal to or superior to the lead zirconate-titanate ceramics at very ... |
|
| Composite Piezoelectric Materials for Transduction |
1994 |
12 pages |
| Authors:
Robert Y. Ting; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| In order to optimize the detection of acoustical signals in a hydrostatic mode for future applications, new transduction materials which combine active ferroelectric materials with other inert phase such as polymers were developed. These new composite piezoelectric materials exhibit hydrostatic piezoelectric coefficients that far exceed what the conventional lead-zirconate- titanate (PZT) ceramics can offer. The particular concept of 0-3 composites is discussed in detail as a typical example of recent ... |
|
| Investigation of a Cylindrical Nonacoustic-Wavenumber Calibration Array |
15 NOV 93 |
127 pages |
| Authors:
L. D. Luker; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| This thesis describes an investigation of a Cylindrical Wavenumber Calibrator (CWC). The CWC is a water-filled device designed to generate nonacoustic-wavenumber pressure fields propagating axially in the water within the calibrator. It can therefore be used to simulate the effects of flow noise on a device placed in the water. The investigation begins with the mathematical analysis of the pressure field inside an infinitely-long, liquid-filled, cylindrical chamber with an axially ... |
|
| Surface Impedance Modification of Plates in a Water-Filled Waveguide |
15 SEP 93 |
30 pages |
| Authors:
Pieter S. Dubbelday; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The interaction of plane waves, propagating in a water-filled cylindrical waveguide with a plate perpendicular to its axis, vith the same cross section as the tube, is determined by the surface impedance at the plate relative to the specific acoustic impedance of the medium. By means of an attached piezoelectric disk-shaped double transducer (sensor and actuator) the apparent surface impedance of the combination may, in principle, be modified to equal ... |
|
| An Analytical Evaluation of Turbulence-Induced Flexural Noise in Planar Arrays of Extended Sensors |
SEP 1993 |
15 pages |
| Authors:
Robert E. Montgomery; Bertrand Dubus; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Large-area, hull-mounted conformal sonar arrays typically employ extended sensors that are configured to detect acoustic signals by means of thickness strains that are induced by the incident pressure field. In most cases, extended sensors also have an appreciable sensitivity to strains in the lateral dimensions. Thus flexure of such a sensor would induce a signal that would not be differentiated from that of a target. Hull-mounted conformal arrays are evolving ... |
|
| Applications of the Method for Transducer Transient Suppression to Various Transducer Types |
AUG 1993 |
10 pages |
| Authors:
J. C. Piquette; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Recently, a new method for suppressing the transient pressure radiation ordinarily produced by a projector in response to drive turn on and turnoff has been described J. C. Piquette, 'Method for transducer transient suppression I. Theory,' J. Acoust. Soc. Am. 92, 1203-1213 (1992) and 'II. Experiment,' J. acoust. Soc. Am. 92, 12141221 (1992). The experiments described in the earlier reports involved application of the method primarily to piezoelectric spherical transducers, ... |
|
| Approximate Evaluation of the Spectral Density Integral for a Large Planar Array of Rectangular Sensors Excited by Turbulent Flow |
JUN 1993 |
9 pages |
| Authors:
Jr. Thompson William; Robert E. Montgomery; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| An approximate numerical procedure has been developed for rapidly evaluating the spectral density integral that predicts the output of a planar array of many sensors excited by turbulent boundary layer pressure fluctuations. This procedure is particularly useful in cases where the transfer function factor of the integrand is not a simple function of the wave numbers in the flow and transverse directions. The procedure exploits the facts that the entire ... |
|
| Elastic Moduli of Aluminum-Polyurethane Composites (ALUMERS) |
15 MAY 93 |
48 pages |
| Authors:
Pieter S. Dubbelday; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| In this report, results are given of the bulk modulus measurement of some selected polyurethanes and of the bulk and Young's modulus of these polyurethanes and composites. These composites consist of a matrix of foamed aluminum impregnated with the various polymers. The composites are named 'alumers', a contraction of 'aluminum' and 'elastomer'. These materials are designed to be approximately transparent to sound, since both density and sound speed are close ... |
|
| Constrained-Layer Damping Analysis for Extensional Waves in Infinite, Fluid-Loaded Plates |
APR 1993 |
11 pages |
| Authors:
Pieter S. Dubbelday; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| This study concerns the mathematical analysis of constrained-layer damping of extensional waves in plates of infinite extent, with and without fluid loading. Previous work was mostly limited to flexural waves. Some aspects of fluid loading for flexural waves may be understood by means of thin-plate theory. Therefore, a similar theory was developed for extensional waves. The description and examples presented here are based on three models: The first is an ... |
|
| Auxetic Materials: An Annotated Bibliography of Materials With Negative Poisson's Ratio |
15 FEB 93 |
23 pages |
| Authors:
Pieter S. Dubbelday; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The purpose of this study was to evaluate the potential of materials with negative Poisson's ratio ('auxetic' materials) for application in hydroacoustics. The results of the literature search were collected in this report in order to facilitate the task of anyone who would like to become familiar with this subject. For an isotropic material, the upper bound of Poisson's ratio v is 1/2. This bound is closely approximated by soft ... |
|
| An Analytical Model for Turbulence-Induced Flexural Noise in Large Conformal Sonar Arrays |
15 JAN 93 |
51 pages |
| Authors:
Robert E. Montgomery; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Large-area, hull-mounted conformal sonar arrays typically employ extended sensors that are configured to detect acoustic signals by means of thickness strains that are induced by the incident pressure field. In most cases, extended sensors also have an appreciable sensitivity to strains in the lateral dimensions. Thus, flexure of such a sensor would induce a signal that would not be differentiated from that of a target. This report presents an analytical ... |
|
| Comment on Time Domain Doppler Estimators of the Amplitude of Vibrating Targets. |
JAN 1993 |
3 pages |
| Authors:
Jean C. Piquette; A. L. Van Buren; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| We have previously pointed out that using linear Doppler effect analysis to evaluate scattering by a vibrating surface produces inaccurate results in acoustics, except under highly specialized conditions. Our objections are based on the fact that medium nonlinearities, and nonlinearities in the fundamental acoustical equations, produce much stronger effects than those predicted on the basis of linear acoustical theory. In the subject paper, it is suggested that our objections do ... |
|
| Elastic Moduli of Aluminum-Polyurethane Composites (Alumers) |
93 |
|
| Authors:
Pieter S. Dubbelday; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
 | This report discusses the measurement of the bulk modulus of pure polyurethanes and the corresponding alumers. possible systematic errors in the measurement of young's modulus are discussed, and a correction model is presented. the results of the measurement of young's modulus e of the alumers are given (the young's modulus of the polyurethanes is taken from the literature). the dilatational wave speed is computed, and the resulting rho c- products ... |
|
| Method for Transducer Transient Suppression. I. Theory |
Sep-1992 |
14 pages |
| Authors:
Jean C Piquette; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The problem of driving a transducer in such a way as to produce a tone burst of steady-sate sound radiation in the surrounding fluid medium is considered. The goal is to determine the driving voltage waveform to apply to a transducer to produce an acoustic pressure waveform in the fluid that is a segment of a steady-state sine wave, beginning and ending at zero crossings of the sine, i.e., the ... |
|
| Low-Frequency Underwater Flex-Beam Transducer |
30 JUL 92 |
16 pages |
| Authors:
T. A. Henriquez; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Acoustic sources that operate at frequencies below 1000 Hz are usually very large if they are required to generate sound power greater than one acoustic watt. Certain naval requirements call for compact low-frequency narrow band acoustic sources. The Naval Research Laboratory's Underwater Sound Reference Detachment has developed a unique underwater acoustic source with the capability of producing high acoustic levels in a small package at a fraction of the cost ... |
|
| Transmission Coefficient Measurement and Improved Sublayer Material Property Determination for Thick Underwater Acoustic Panels: A Generalization and Improvement of the ONION Method |
Jul-1992 |
13 pages |
| Authors:
Jean C Piquette; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Modifications of the ONION panel-measurement method that allow for simultaneous analysis for transmitted- and reflected-wave data are described. The revised algorithm determines more reliable values for the sound speed and loss of the material of each panel sublayer than does the algorithm that is based exclusively upon analysis of the reflected wave. Included in the revised method is a Taylor series expansion of the sound-speed function of each layer about ... |
|
| Direct Measurement of the Temperature-Dependent Piezoelectric Coefficients of Composite Materials by Laser Doppler Vibrometry |
Apr 1992 |
9 pages |
| Authors:
Kurt M Rittenmyer; Pieter S Dubbelday; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The longitudinal (d33) and transverse (d3l) piezoelectric coefficients of a piezoelectric composite material (NTK PR-306) are determined as functions of frequency and temperature by using laser Doppler vibrometry to measure the strain induced in the sample by an electric field. Measurements are performed over the temperature range from 50 deg C to 50 degC and over a frequency range from 0.1-10 kHz. Some measurements were made at frequencies up to ... |
|
| Analysis of Constrained-Layer Damping of Flexural and Extensional Waves in Infinite, Fluid-Loaded Plates |
MAR 92 |
8 pages |
| Authors:
Pieter S. Dubbelday; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| This study contains a mathematical analysis of constrained-layer damping (CLD) in plates of infinite extent, with an emphasis on the physical understanding of some special features, including fluid loading. Previous work is expanded to cover extensional waves. Some essential aspects of fluid loading may be understood by applying thin-plate theory. Therefore, thin-plate theory of extensional waves in a fluid-loaded plate was developed as a counterpart to that for flexural waves. ... |
|
| Evaluation of the Properties of 1-3 Piezocomposites of a New Lead Titanate In Epoxy Resins |
Jan 1992 |
11 pages |
| Authors:
Robert Y Ting; Avner A Shaulov; Wallace A Smith; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| By using a new calcium-modified lead titanate ceramic with a near- zero planar coupling coefficient, a series of 1-3 piezocomposite samples was fabricated with a dice-and-fill technique. The ceramic rods were approximately 0.10 mm in size, and the percent of ceramic loading varied from 10 to 30%. Two epoxy resins with different glass transition temperatures and moduli were used. The dielectric properties and temperature and the piezoelectric dh and gh ... |
|
| Influence of Cure Systems on Dielectric and Viscoelastic Relaxations in Crosslinked Chlorobutyl Rubber |
1992 |
15 pages |
| Authors:
Rodger N. Capps; Christopher S. Coughlin; Linda L. Beumel; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The temperature and frequency-dependent Young's modulus and loss tangent have been examined as functions of cure systems and plasticizer loading in chemically crosslinked butyl and chlorobutyl rubbers. The crosslinked materials exhibited thermorheologically simple behavior. Dielectric permittivity and loss were measured as functions of frequency and temperature. The viscoelastic and dielectric behaviors were significantly influenced by the type of crosslinking system and by plasticizer loading. The Kolrausch-Williams-Watts 'stretched exponential' function was ... |
|
| Stabilization of a Digitally Controlled Active-Isolation System, |
Apr 1991 |
19 pages |
| Authors:
S E Forsythe; M D McCollum; A D McCleary; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Digital control techniques have roved beneficial in many control applications because the are flexible and lend themselves to adaptive implementation. However, in control system that require feedback rather than feedforward as the control mechanism, the advantages of digital control are offset by the difficulty of designing stable controllers. The time lag introduced by anti-aliasing filters. These lags, in conjunction with low sampling rates, make an otherwise stable system subject to ... |
|
| Electromechanical Modelling of an Active Isolation System |
Apr 1991 |
19 pages |
| Authors:
D McCollum; S E Forsythe; A D McCleary; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Reprint: Electromechanical Modelling of an Active Isolation System. |
|
| Near-Field Transmitting and Receiving Properties of Planar Near-Field Calibration Arrays |
Mar 1991 |
7 pages |
| Authors:
van; Arnie L Buren; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
|
| Variable Projection Methods with Application to Sums of Exponentials in White Noise |
27 DEC 90 |
115 pages |
| Authors:
P. L. Ainsleigh; J. D. George; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| We examine Nonlinear Least-Squares (NLS) methods for estimating the pole and amplitude parameters for a sum of damped and undamped sinusoids observed in white noise. A special case of NLS, which takes advantage of the semilinear structure of this signal model, involves minimization of the Variable Projection Functional (VPF). The VPF offers computational efficiency by providing a means of estimating the signal poles independently of the amplitudes. We extend the ... |
|
| DISPLAY3D. A Graphics Preprocessor for CHIEF |
27 DEC 90 |
91 pages |
| Authors:
C. M. Siders; D. M. Bolling Jr; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The computer program CHIEF (G.W. Benthien, D. Barach, and D. Gillette, CHIEF Users Manual, Naval Ocean Systems Center Report 920, Sep 88) is designed to obtain approximate solutions to exterior steady-state acoustic radiation problems for surfaces of arbitrary shapes vibrating with a prescribed normal velocity. Being unable to view the shapes defined by CHIEF can lead to many difficult debugging problems as well as incorrect solutions. DISPLAY3D provides points as ... |
|
| A Low-Frequency, Tow-Powered Sound Source |
JUN 90 |
23 pages |
| Authors:
J. E. Blue; A. L. Van Buren; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| This paper discusses resonant cavities and their potential sound pressure output when they are modulated hydrodynamically. Rough calculations show that in the frequency range of 10 to 100 Hz source levels in excess of 200 dB re 1 micro Pa should be achievable. Experimental data from three suboptimum devices showed source levels of 182 dB at 16.6 and 50 Hz and 168 dB at 34.5 Hz. It is expected that ... |
|
| A Planar Array for the Generation of Evanescent Waves |
Jun 1990 |
7 pages |
| Authors:
D H Trivett; L D Luker; S Van Petrie; A L Buren; Joseph E Blue; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Wavenumber-frequency calibration of underwater, planar, receiving arrays requires the ability to generate single-wavenumber pressure fields over the surface of the array. When the wavenumber-frequency region of interest is evanescent, transmitting arrays previously constructed have been found to generate fields contaminated with harmonics, acoustic wavenumbers, and nonacoustic wavenumbers from the excitation of the antisymmetric Lamb waves. An array that greatly reduces contamination has recently been constructed using a sheet of polyvinylidene ... |
|
| Offnormal Incidence Reflection-Coefficient Determination for Thick Underwater Acoustic Panels Using a Generalized ONION Method |
Apr 1990 |
14 pages |
| Authors:
Jean C Piquette; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The ONION method is a reflection-coefficient measurement technique designed for use on data acquired from thick underwater acoustic panels in the frequency range 1-10 kHz, but may be used to frequencies as high as 25 kHz. The method extrapolates transient reflected-wave data using least-squares fitting to a multiple-layer panel model. A description of the method, as it applies to data acquired using a normally incident interrogating wave, is provided in ... |
|
| Bulk Modulus of Partially Fluorinated Epoxies |
Apr 1990 |
5 pages |
| Authors:
Corley M Thompson; Lesli M Leimer; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
|
| Development of a Structurally Rigid, Acoustically Transparent Plastic |
Mar 1990 |
8 pages |
| Authors:
Corley M Thompson; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Some underwater acoustical applications require a window that is both acoustically transparent and structurally rigid. No previous material possesses those properties, the closest being Poly(4-methyl-pentene) (PMP) plastic, whose specific acoustic impedance is 17% higher than seawater. A series of partially fluorinated epoxies is described that have sound speeds near water, but densities that are more than 50% higher than water. When these fluoro-epoxies are compounded with glass microspheres to lower ... |
|
| Piezoelectric Properties of 1-3 Composites of a Calcium-Modified Lead Titanate in Epoxy Resins |
Jan 1990 |
6 pages |
| Authors:
Robert Y Ting; Aver A Shaulov; Wallace A Smith; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| A series of 1-3 piezocomposite samples were fabricated by using lead titanate ceramic with a dice-and-fill technique. The ceramic rods were approximately 0.10 mm in size, and the ceramic volume fraction varied from 10 to 30%. Two different epoxy resins were used. The piezoelectric dh and gh coefficients of the composites were found to be stable with pressure from ambient to 20 MPa. The temperature dependence of the composite properties ... |
|
| Transducer Needs for Low-Frequency Sonar |
90 |
28 pages |
| Authors:
R. W. Timme; A. M. Young; J. E. Blue; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The continued advances in the acoustic quieting of submarines may necessitate the use of active sonar as an adjunct to the traditional passive sonar as a means of detecting submarines. Therefore, there is a growing need for transducers that produce sound underwater at frequencies below 1000Hz. However, reality is such that it is very difficult to design for low frequency, high power, and high efficiency and still maintain a device ... |
|
| Calibration of Underwater Acoustic Transducers at NRL/USRD |
90 |
48 pages |
| Authors:
A. L. Van Buren; J. E. Blue; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| At the beginning of World War II, the United States recognized the need for establishing systematic methods for calibrating and evaluating sonar transducers and established the Underwater Sound Reference Laboratories. The Underwater Sound Reference Detachment of the Naval Research Laboratory evolved from this beginning and now serves as the focus for underwater acoustic metrology in the United States. It functions as a National Bureau of Standards for Underwater Acoustics by ... |
|
| The Shock Test Facility: An Explosive-Driven, Water-Filled Conical Shock Tube |
NOV 89 |
8 pages |
| Authors:
J. F. Zalesak; L. B. Poche Jr; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
|
| Elastomeric Materials for Acoustical Applications |
15 SEP 89 |
332 pages |
| Authors:
Rodger N. Capps; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| A background discussion of polymer viscoelasticity is given. Methods of polymer characterization are discussed. Factors in the compounding and vulcanization of elastomeric materials which affect end-product performance are also discussed. General information and cure systems are discussed for a number of different classes of rubber materials. Dynamic mechanical properties of a number of elastomeric materials are graphically presented. Compounding recipes and cure conditions are included, as well as the static ... |
|
| Some Strip Contributions to Transducer Design and Analysis |
28 APR 1989 |
|
| Authors:
David L. Carson; Alan K. Walden; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| This book explains certain transducer design developments resulting from the Sonar Transducer Reliability Improvement Program, such as the Simplified Guidance Model for k33-mode transducer elements. The model's usefulness in understanding and explaining certain transducer design techniques for a 33-mode projector element and array is discussed. The model is augmented and applied such that it may be used 1) as an educational tool to help inexperienced transducer design engineers acquire some ... |
|
| Dynamic Mechanical Testing. Application of Polymer Development to Constrained-Layer Damping |
APR 89 |
|
| Authors:
Rodger N. Capps; Linda L. Beumel; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Viscoelastic materials are widely used for acoustic attenuation, isolation of continuous vibration, and shock mountings. The properties of these materials are dependent upon temperature and frequency of excitation, molecular structure of the base polymer, and chemical cross-linking systems and fillers. This paper describes a transfer function technique for the measurement of the frequency-dependent Young's modulus and loss tangent. Algorithms for time- temperature superposition are also discussed. It is then shown ... |
|
| The Effect of Annealing on the Thermal and Dynamic Mechanical Properties of TMXDI Based Polyurethanes |
Jan 1989 |
11 pages |
| Authors:
G M Stack; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Reprint: The Effect of Annealing on the Thermal and Dynamic Mechanical Properties of TMXDI Based Polyurethanes. |
|
| Modified-Lead-Titanate/Polymer Composites for Hydrophone Applications |
Jan 1989 |
8 pages |
| Authors:
Avner A Shaulov; Wallace A Smith; Robert Y Ting; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| Composite piezoelectrics made from Calcium modified lead titanate rods embedded in a polymer matrix have been evaluated for hydrophone applications. These composites behave quite differently form the conventional 1- 3 composites made with lead zirconate titanate ceramics. Specifically, in the modified lead titanate case the magnitude of the d31 coefficient is enhanced in the composite structure, and consequently the hydrostatic dh coefficient is suppressed. Nevertheless, these composites exhibit a large ... |
|
| Detection of Fluid Velocity and Hydroacoustic Particle Velocity Using a Temperature Autostabilized Nonlinear Dielectric Element (TANDEL) |
DEC 1988 |
6 pages |
| Authors:
Kurt M. Rittenmyer; George C. Alexandrakis; Pieter S. Dubbelday; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| A ferroelectric sensor operated in the temperature auto-stabilized mode was developed for the measurement of the particle motion in hydroacoustic fields. The sensor is a capacitor-like element constructed from antimony sulfur iodide (SbSI) single crystals and SbSI-polymer composites. The device is operated slightly above the Curie point of SbSI which is approximately 20 C. Using a Schering bridge, the element is heated by driving it through the hystersis cycle. The ... |
|
| Spherical-Wave Scattering by a Finite-Thickness Solid Plate of Infinite Lateral Extent, with Some Implications for Panel Measurements |
APR 1988 |
18 pages |
| Authors:
Jean C. Piquette; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| The solution to the problem of the interaction of spherical wave with a homogenous and isotropic solid state plate of infinite lateral extent, but finite thickness, is considered theoretically. Both the source and the plate are immersed in an infinite, inviscid fluid. Appropriate boundary conditions are imposed on the full three-dimensional elasticity equations. The solution is evaluated numerically for a variety of materials for a 1kHz incident spherical wave an ... |
|
| Underwater Helmholtz Resonator Transducers for Low-Frequency, High-Power Applications |
Jan 1987 |
11 pages |
| Authors:
A M Young; T A Henriquez; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
|
| Some Further Remarks Regarding Scattering of an Acoustic Wave by Vibrating Surface |
NOV 1986 |
7 pages |
| Authors:
Jean C. Piquette; A. L. Van Buren; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| This letter considers in detail plane wave scattering by a vibrating plane and thereby demonstrates analytically that Censor's theory predicts sum and difference frequency component waves that are of the order of magnitude of pseudosound. This example also illustrates that the parametrically growing sum difference frequency component waves generated nonlinearly overwhelm those predicted by the Censor theory within a fraction of a wavelength of the scatterer's surface. |
|
| Extensional-Wave and Flexural-Wave Contributions to the Sound Field Radiated by a Fluid-Loaded Infinite Plate |
SEP 86 |
|
| Authors:
Anthony J. Rudgers; Pieter S. Dubbelday; Lisa A. Fagerstrom; NAVAL RESEARCH LAB ORLANDO FL UNDERWATER SOUND REFERENCE DETACHMENT
|
| A structural thick plate theory that accounts for the propagation of both extensional and flexural waves in an infinite elastic plate is used to calculate the farfield directional response of the sound radiated by a plate with fluid on one side. The plate is driven by a harmonic point force, and the radiation in the farfield of the driving point is considered. Computations are made for metal plates and plates ... |
|
Reports by Corporate Author
