Topics: DTIC Archive, NAVAL ACADEMY ANNAPOLIS MD, *BOUNDARY VALUE PROBLEMS, BONDED JOINTS, SHEAR STRESSES,...
A discussion of wind shear in the jet stream over White Sands Missile Range, New Mexico is presented. Wind data collected utilizing the GMD-1 system are used to calculate vectorial wind shear. The maximum jet wind speed could not be significantly correlated to the maximum wind shear for any particular observation. Mean vectorial wind shear and standard deviation for each thousand feet of height in the jet stream are included.
Topics: DTIC Archive, ARMENDARIZ, MANUEL, WHITE SANDS MISSILE RANGE NM, *JET STREAMS, *SHEAR STRESSES, *WIND
A photoelastic analysis was made of the shear stress distribution in an .064-inch aluminum alloy, adhesive-bonded lap joint. The adhesive that was used was a photoelastic material. The stress distribution was studied directly on the adhesive itself in the joint as a function of increasing load and length of overlap of the adherends. The experimental distribution that was obtained was compared with that predicted by the theoretical analysis of Goland and Reissner.
Topics: DTIC Archive, FOREST PRODUCTS LAB MADISON WI, *BONDED JOINTS, ALUMINUM ALLOYS, PHOTOELASTICITY,...
Recent theoretical work has predicted that the intrinsic viscosity of very long chain polymers in viscous solvents should increase with increasing shear gradient. Highly viscous solvents are required to develop sufficient shearing forces to overcome the inner viscosity (rigidity) of the polymer coil. This report concerns experimental work directed toward examination of the theory. Two polyphenylene oxide fractions, 1290,000 and 345,000 molecular weight, in pyralene and two polyisobutylene...
Topics: DTIC Archive, UPPSALA UNIV (SWEDEN), *POLYMERS, SOLUTIONS(MIXTURES), MOLECULAR WEIGHT, SHEAR...
In this investigation, theoretical expression are developed for the threshold stress of plastic deformation and for the periodic spacing of deformation-induced dislocation microstructure in face-centered cubic materials. The process of plastic deformation in these materials, dislocation cross-slip, is modeled on the micro-scale (10-6m). This micro-scale mode is transformed into a macro-scale (structural component scale) engineering tool using the homogenization process, a form of volume...
Topics: DTIC Archive, Bagley, Ronald L., TEXAS UNIV AT SAN ANTONIO, *PLASTIC DEFORMATION, *SIMPLE CUBIC...
CONTENT: Introduction (Equipment - General -Test samples) * Basics (Material removal - Roughness changes - Shear stress removal - Temperature increase - Sample distribution - Different media) * End-roughness and micro structure of different C-steels * Material removal and roughness changes versus the amount of treatment solution in the bowl * Material removal and roughness changes versus pH * Comparing the performance of a commercially available acid treatment solution with 0.5 M Ammonium...
Topics: DTIC Archive, NORTH DAKOTA UNIV GRAND FORKS, *ROUGHNESS, *SURFACE FINISHING, *CORROSION, SYMPOSIA,...
The report documents the results of a limited number of static and dynamic tests on one tuff from the location of the Diamond Mine Event tunnel at the Nevada Test Site. The tests comprised the first experimental study conducted in the then newly developed dynamic high-pressure triaxial test device. The purpose of the study was to determine loading rate effects on the uniaxial strain, hydrostatic compression, and triaxial shear response of that tuff when loaded statically (approximately 2...
Topics: DTIC Archive, Ehrgott, John Q, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS, *ROCK,...
The objective of this research is to study the blood flow close to the wall of a stented artery. Indeed, previous works have showed that the restenosis phenomenon is induced by the endothelial cells stimulation due to the wall shear stress values, The coronary angioplasty is responsible of wall shear stress modification, mainly between the stent struts, at the inlet and the outlet of the endoprothesis. That is why, to study the flow disturbances through a stented section, we built an in vitro...
Topics: DTIC Archive, Benard, N, POITIERS UNIV (FRANCE), *LAMINAR FLOW, *CORONARY ARTERIES, *STENTS, SHEAR...
Sandwich panels were fabricated in the laboratory using FMS-0015 (skin-to-core) and FMS-0016 (metal-to-metal) adhesives, glass reinforced plastic honeycomb core, 7075T-6 aluminum slugs and 2024T-86 aluminum skins and evaluated before, after and during a five year exposure period to outdoor weather. The following tests were used to evaluate the effect of exposure : 260 F core shear and shear modulus of rigidity, 260 F edgewise compression, 260 F accelerated column-beam creep, R. T. simple beam,...
Topics: DTIC Archive, THOMAS, J E, GENERAL DYNAMICS CORP FORT WORTH TX, *ADHESIVES, CLIMATE, FUELS,...
The objective was to ascertain the magnitude of forces responsible for coherency of rock by quantifying the strength of the attractive forces operating between minerals in rock. These forces oppose stresses set up in various rock fragmentation processes, hence strength measurements of these forces might prove useful in designing more efficient rock fragmentation methods. Methods were developed for estimating strength of intergranular adhesion in rock. Examination of bicrystals broken at the...
Topics: DTIC Archive, Savanick, George A, *GRAIN BOUNDARIES, *ROCK, *ROCK FORMING MINERALS, ADHESION,...
Solutions for the maximum resolved shear stresses on twinning systems in fcc and bcc crystals in tension and compression are presented and discussed. Additional data are included on the relative magnitudes of shear stresses on secondary systems. Conventions for the specification of twinning systems are described and discussed.
Topics: DTIC Archive, Kingman, Priscilla W, ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD,...
The Lueders band propagation rate, s sub L, in low carbon steel can be considered to obey the relation, s sub L = s sub zero exp-(H(Tau)/kT) where s sub zero is approximately a constant, and H(Tau) is the activation energy of the process, and represents a decreasing function of the effective stress, Tau (given by the difference between the applied stress and the long-range internal stress). Available data on the effect of stress on Luders band velocity is correlated on the basis of this...
Topics: DTIC Archive, Conrad, Hans, AEROSPACE CORP EL SEGUNDO CA, *STRESSES, *CARBON STEELS, REACTION...
The effect of rate of strain on shear strength of cohesive soils of marine sediments were studied. Vane shear (apparatus) tests were performed on an ocean sediment at varying permeabilities with various rates of shear. A variation in shear strength as high as 46.4% have been found over the range of rotation rates used in this experiment. Suggestions for further experimentation in this area are included.
Topics: DTIC Archive, Halwachs, James E, NAVAL ACADEMY ANNAPOLIS MD, *OCEAN BOTTOM, DEFORMATION,...
Topics: DTIC Archive, AEON LABS EGHAM (UNITED KINGDOM), *MICROTOMES, *METALS, DEFORMATION, SHEAR STRESSES,...
Characteristics of the wind shear for 25 meter layers were prepared from a series of 175 detailed wind ascents to 18 km taken with a Jimsphere balloon followed by FPS-16 radar from November 1964 to June 1965. To determine how well the shears for small layers could be estimated from rawinsonde data, two new sets of ascents were created from the original Jimsphere data. One set consisted of wind data at 23 levels corresponding only to standard pressure levels, and the other set at the 46 'minute'...
Topics: DTIC Archive, Belmont, A D, CONTROL DATA CORP MINNEAPOLIS MN RESEARCH DIV, *WIND, METEOROLOGICAL...
The results of shear tests on the system ice/stainless steel and ice/ optically flat fused quartz as a function of the rate of shear and roughness of the steel surface are reported. The adhesive strength decreased with decreasing roughness of steel surfaces, and the force-vs-time curves for smooth steel plates resembled those of 2 solids sliding over each other with a liquid layer between. This behavior was especially evident in the case of quartz. The adhesive strength as a function of rate of...
Topics: DTIC Archive, SNOW ICE AND PERMAFROST RESEARCH ESTABLISHMENT WILMETTE IL, *ICE, ADHESION, STAINLESS...
Topics: DTIC Archive, HAYTHORNTHWAITE, R M, BROWN UNIV PROVIDENCE RI, *SOIL MECHANICS, *TRIAXIAL STRESSES,...
Topics: DTIC Archive, BUNKER, ANDREW F., WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *MARINE METEOROLOGY,...
This paper reviews existing microelectromechanical systems (MEMS)-based shear stress sensors. The promise and progress of MEMS scaling advantages to improve the spatial and temporal resolution and accuracy of shear stress measurement is critically reviewed. The advantages and limitations of existing devices are discussed. Finally, unresolved technical issues are summarized for future sensor development.
Topics: DTIC Archive, Sheplak, Mark, FLORIDA UNIV GAINESVILLE MECHANICAL AND AEROSPACE ENGINEERING,...
The mixed-mode, elasto-dynamic state of stresses in the neighborhood of a rapidly running crack tip has been used to develop a relation between the isochromatic fringe order and its position parameters. The maximum shear stress is expressed in terms of the stress intensity factors and other higher order terms involving the mixed-mode loading for a crack propagating at constant velocity. A graphics package based on these derivation was developed for mapping the isochromatics in the vicinity of a...
Topics: DTIC Archive, Ramulu,M, WASHINGTON UNIV SEATTLE DEPT OF MECHANICAL ENGINEERING,...
The ROSE balloon/AN-FPS-16 radar system is designed to report small- scale winds and shears by polynomial smoothing of the radar tracking data. The most successful mathematical technique for fitting the data and computing winds and shears is presented along with other techniques which were considered but ultimately rejected. Analysis of the self-induced balloon motion is attempted by classical physical methods and by a Power Spectral Density Technique. A criterion for evaluating the effect of...
Topics: DTIC Archive, DAYTON UNIV OH RESEARCH INST, *METEOROLOGICAL BALLOONS, MATHEMATICAL ANALYSIS,...
Cleavage (brittle) fractures, have been investigated extensively. Proof-test failures involving 'low energy shear' fractures have been encountered under conditions of near-yield-point loading for structures (rocket cases) which utilized high-strength materials. This investigation was undertaken to develop a test method which would provide for the evaluation of tearing characteristics under explosive loadings for steels ranging in yield strength from 100 to 150 ksi. A new test, the explosion...
Topics: DTIC Archive, PUZAK, P P, NAVAL RESEARCH LAB WASHINGTON DC, *SHEAR STRESSES, *STEEL, ALLOYS,...
Topics: DTIC Archive, SUTTER, R C, FRANKFORD ARSENAL PHILADELPHIA PA PITMAN-DUNN RESEARCH LABS, *EXPLOSIVE...
The development of novel, fouling-release surfaces has led to the need for better test methods to evaluate their performance. A water channel has been designed to measure the adhesion strength of microfouling organisms to test surfaces. The apparatus allows six replicate microscope slides to be mounted in a fully-developed, turbulent channel flow. Wall shear stress in the test section can be varied from 0.9-30 Pa over a Reynolds number range of 2,800 to 27,000 based on the bulk mean velocity...
Topics: DTIC Archive, NAVAL ACADEMY ANNAPOLIS MD DEPT OF MECHANICAL ENGINEERING, *ADHESION, *FOULING...
Under dynamic loading conditions associated with shock motions, hold-down bolts may be subjected to both shear and tensile stresses. If the bolt holes in the shear plane are chamfered so as to permit the bolt to deform in shear and bending along its length, the amount of energy absorbed by the bolt before fracture is increased when shear motions are encountered. The amount of energy absorbed when a 45-degree chamfer was employed was a constant (the energy absorbed by a bolt in shear with no...
Topics: DTIC Archive, Vigness, I, NAVAL RESEARCH LAB WASHINGTON DC, *LOAD DISTRIBUTION, *TENSILE...
An ektacytometric instrumentation system was set-up in the laboratory and its usefulness in red blood cell (RBC) preservation studies was evaluated. Ektacytometry provides a measure of cell deformability by determining the elongation of the cells under fluid shear stress using laser diffractometry and image analysis. In order to objectively assess the data obtained with red blood cell samples, it was necessary to establish that neither white blood cell concentration nor freezing in 40% W/V...
Topics: DTIC Archive, Colmer,K, BOSTON UNIV MA SCHOOL OF MEDICINE, *Blood preservation, *Erythrocytes,...
The surface-wave inspection method, based on Lamb wave propagation, appears promising for detecting cracks and for evaluating the size of the bonded area. Further development work and extensive evaluation of this inspection technique would be required, however, to demonstrate the validity and practicality of this weld-inspection method.
Topics: DTIC Archive, AEROPROJECTS INC WEST CHESTER PA, *HEAT RESISTANT ALLOYS, *ULTRASONIC WELDING, SHEAR...
Topics: DTIC Archive, Orr, Raymond L., Bainbridge, Douglas W., CALIFORNIA UNIV BERKELEY MATERIALS RESEARCH...
The object of this report was to study the shear strength of a structural adhesive used in Army helicopters as a function of strain rate and failure time at several temperatures. Shear strengths of adhesive AF126 bonds to two thicknesses of aluminum were measured at constant rate of crosshead separation. Primarily cohesive failure was observed in all cases. By using relations proposed by Cherry and Holmes, the shear strength could be quantitatively related to temperature and strain rate or...
Topics: DTIC Archive, McAbee, Elise, PICATINNY ARSENAL DOVER NJ, *ADHESIVES, *BONDED JOINTS, ALUMINUM...
A few aspects of the ultrasonic influence on the plasticity of metals are treated in this aper. It is shown that with purest zinc crystals the recovery from the cold-hardened condition (measured as the decrease of the shearing stress of the basal plane) is accelerated by an ultrasonic treatment during the period of recovery. Also the second softening mechanism - recrystallization by way of nucleation and growth of crystals - is activated at certain temperatures by ultrasonic influences, as is...
Topics: DTIC Archive, VIENNA UNIV (AUSTRIA), *METALS, *DEFORMATION, *ULTRASONIC RADIATION, SHEAR STRESSES,...
Topics: DTIC Archive, AEROPROJECTS INC WEST CHESTER PA, *PHOTOELASTICITY, *ULTRASONIC RADIATION, *WELDING,...
A theoretical solution is given for the critical shear stress of an infinitely long, simply supported, flat plate with identical, equally spaced, transverse stiffeners of zero torsional stiffness. Results are obtained by means of the Lagrangian multiplier method and are presented in the forms of design charts. Experimental results are included and are found to be in good agreement with the theoretical results.
Topics: DTIC Archive, Stein, Manuel, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC, *SHEAR...
Topics: DTIC Archive, LETH, CARL-FREDRIK A., BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS,...
Topics: DTIC Archive, Holmboe, Jorgen, CALIFORNIA UNIV LOS ANGELES, *CYCLONES, *ATMOSPHERE MODELS,...
A quasi-geostrophic omega equation for largescale vertical velocities in the atmosphere is solved at the earth's surface, 850-, 700-, 500-, and 300-mb levels for a grid of 1977 points per level covering the major portion of the Northern Hemisphere. The effects of terrain and surface frictional stress on the vertical velocity at the lower boundary are investigated in some detail and applied at the earth's surface. The three-dimensional integration of the resulting equations excludes areas inside...
Topics: DTIC Archive, Clarke, Lee C, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *ATMOSPHERES, *BAROMETRIC...
Predictions of the ocean dynamics, sediment transport, pollutant dispersal and biological processes require knowledge on the characteristics of turbulence in the bottom boundary layer. Modeling of the turbulence requires data for development/validation of closure models.
Topics: DTIC Archive, JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF MECHANICAL ENGINEERING, *BOUNDARY LAYER,...
The objective of this program was to develop design procedures and durability validation methods for curved metal and composite panels designed to operate in the postbuckling range under the action of combined compression and shear loads. This research and technology effort was motivated by the need to develop design and life prediction methodologies for such structures.
Topics: DTIC Archive, Deo, R B, NORTHROP CORP HAWTHORNE CA AIRCRAFT DIV, *COMPOSITE MATERIALS, *PANELS,...
The long-term objective for this research is to use our improved knowledge of the TKE, Reynolds stress, and scalar flux budgets to develop and test parameterizations of mixed layer dynamics and deep penetrative convection and overturning for inclusion in basin-scale oceanic general circulation models. principal technical objective is to simulate and understand the behavior of Lagrangian drifters and floats in the presence of deep convection in the Labrador Sea. The corollary scientific...
Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF OCEANOGRAPHY, *FLUID MECHANICS,...
The work funded by this grant addressed robust methods for estimation of dissipation rate and Reynolds stress based on turbulence measurements in the coastal ocean. The work resulted in two publications. The first was an evaluation, based primarily on intensive laboratory tests, of the acoustic Doppler velocimeter (ADV) as a turbulence sensor. The second was a description, based on theoretical considerations and a field test, of a novel technique for measuring Reynolds stress in the presence of...
Topics: DTIC Archive, Trowbridge, John H., WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *TURBULENCE, *SHEAR...
Optimization of a emulsified fuel (MEF) was accomplished following evaluation of a 168 formulation matrix. Thermal and storage stability was best when a 1% to 2% excess of acid was used to neutralize the tallow amine emulsifier. Emulsion droplet size was shown to be more a function of preparation than of thermal effect or aging. Attempts at improvement of an MEF- 1 formulation from the investigation by using coupling agents or corrosion inhibitors were unsuccessful. However, change in...
Topics: DTIC Archive, Harris, Jay C, MONSANTO RESEARCH CORP DAYTON OH DAYTON LAB, *JET ENGINE FUELS, *GELS,...
This report presents the first semi-empirical solution suggested to describe the traction versus slip relationship for rigid wheels. The kinematics of a slipping wheel are analyzed and the results are used to express the shear deformation as a function of slip which in turn is utilized in a new shear stress-strain relationship. The shear stresses are expressed at every point of the tire-soil interface surface and integrated to obtain the traction. Other established information is also briefly...
Topics: DTIC Archive, ARMY TANK-AUTOMOTIVE CENTER WARREN MI, *TIRES, *TRAFFICABILITY, STRESSES,...
A theory for the dynamic elasto-plastic deformations of thin shells is presented. The deformation is obtained by equating the energy input to the energy absorbed by the structure. Large deflections and strain hardening are considered. The theory is applied to the case of a shell undergoing axially symmetric collapse.
Topics: DTIC Archive, J G ENGINEERING RESEARCH ASSOCIATES BALTIMORE MD, *LOADS(FORCES), *SHELLS(STRUCTURAL...
Topics: DTIC Archive, CHOI, H S, NOTRE DAME UNIV IN DEPT OF METALLURGICAL ENGINEERING AND MATERIALS...
The experimental evidence on mechanical behavior of fcc, bcc and hcp metals is briefly reviewed. Extended linear hardening, largely independent of temperature, strain rate and other testing conditions, is found not only in all fcc metals (stage II) and in Ge but also in polycrystalline Fe and simple steels. The average value of the shear modulus by work hardening coefficient in the linear range is about 300 in fcc metals and 500 in steels. The corresponding value for hcp metals is by far...
Topics: DTIC Archive, Wilsdorf, Doris, PENNSYLVANIA UNIV PHILADELPHIA SCHOOL OF METALLURGICAL ENGINEERING,...
A micro electro mechanical system (MEMS) was designed, manufactured, and vibrationally tested. The system consisted of a multitude of nearly identical shear stress sensors. The resonant frequency was measured to 57 sensors with a mean frequency of 90.037 KHZ and a standard deviction of 0.297 KHZ. Although attempted in water, only the air measurements were conducted.
Topics: DTIC Archive, Jonson, Michael, PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB,...
A feasibility study was made of the use of magnetic fields controlling shear stresses in magnetizable fluids and of electric fields controlling shear stresses in electrically active fluids, for driving a high- power, high-frequency vibration and shock exciter. This report is concerned with the actual design, construction, and testing of a prototype shock-shaker. A theoretical analysis of the electric-fluid mechanics is presented. The prototype demonstrated the technical feasibility of...
Topics: DTIC Archive, Eige, John J, STANFORD RESEARCH INST MENLO PARK CA, *VIBRATION, *ELECTRIC FIELDS,...
Data are given for shear and tensile testing of adhesive bonds under a constant rate of loading. A rate equation is then used to predict useful life from the mechanical data. The correlations are in general quite satisfactory, providing that the failure is cohesive within the adhesive.
Topics: DTIC Archive, McAbee, Elise, PICATINNY ARSENAL DOVER NJ, *BONDED JOINTS, LIFE EXPECTANCY(SERVICE...
Constant stress experiments, recovery and multi-step creep tests in torsion in the nonlinear range were performed at different temperatures up to 160F. It was found that the results could be described by a power function of time whose exponent was independent of stress and temperature. Most of the temperature effect and most of the nonlinearity were found in the coefficient of the time-dependent term. The nonlinearity was described by the multiple integral representation, and the changes in...
Topics: DTIC Archive, Lai, J S, BROWN UNIV PROVIDENCE RI ENGINEERING MATERIALS RESEARCH LAB, *TEMPERATURE,...
A method is outlined for multi-region pressure vessels design calculations using the maximum shear theory. This treatment is employed due to the simplicity of the method and because the results are quite conservative for both ductile and brittle materials. A procedure for obtaining an optimum design is given for a desired percentage of auto-frettage on the inner wall of the pressure vessel. A computer program was written in Fortran II language and the various design possibilities were executed...
Topics: DTIC Archive, Leyenaar, Antonio R, MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB, *PRESSURE...
The present report extends the combined variable moduli model introduced in the previous report. This more general model is defined, conditions are set on the various parameters, and the model behavior in uniaxial strain, triaxial compression and proportional loading tests is discussed. The major portion of the present report deals with the procedures used to fit the current model, including the loading and unloading, to a rather complete set of laboratory data for McCormick Ranch Sand....
Topics: DTIC Archive, Nelson, Ivan, WEIDLINGER ASSOCIATES NEW YORK, *NUCLEAR EXPLOSIONS, *SOIL MECHANICS,...
