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

Topics: DTIC Archive, NAVAL ACADEMY ANNAPOLIS MD, *BOUNDARY VALUE PROBLEMS, BONDED JOINTS, SHEAR STRESSES,...

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,...

Topics: DTIC Archive, Holmboe, Jorgen, CALIFORNIA UNIV LOS ANGELES, *CYCLONES, *ATMOSPHERE MODELS,...

Topics: DTIC Archive, BUNKER, ANDREW F., WOODS HOLE OCEANOGRAPHIC INSTITUTION MA, *MARINE METEOROLOGY,...

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...

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,...

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,...

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...

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,...

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...

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,...

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,...

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,...

Topics: DTIC Archive, LETH, CARL-FREDRIK A., BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS,...

Topics: DTIC Archive, HAYTHORNTHWAITE, R M, BROWN UNIV PROVIDENCE RI, *SOIL MECHANICS, *TRIAXIAL STRESSES,...

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 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...

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...

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...

Topics: DTIC Archive, Orr, Raymond L., Bainbridge, Douglas W., CALIFORNIA UNIV BERKELEY MATERIALS RESEARCH...

Topics: DTIC Archive, AEROPROJECTS INC WEST CHESTER PA, *PHOTOELASTICITY, *ULTRASONIC RADIATION, *WELDING,...

Topics: DTIC Archive, SUTTER, R C, FRANKFORD ARSENAL PHILADELPHIA PA PITMAN-DUNN RESEARCH LABS, *EXPLOSIVE...

By means of experimental and numerical analysis, turbulent flow separation has long been extensively studied. This is not only due to its interesting intrinsic flow features for fundamental studies, but also for its significance in engineering applications in relation to, among others, turbulent heat transfer, drag and noise generation. In the presence of sharp edges, protuberances, curvature surfaces and/or adverse pressure gradient, boundary layer separation is usually accompanied with free...

Topics: DTIC Archive, Peng,Shia-Hui, Swedish Defence Research Agency FOI Sweden, turbulent flow, shear...

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...

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,...

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...

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...

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 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...

Topics: DTIC Archive, AEON LABS EGHAM (UNITED KINGDOM), *MICROTOMES, *METALS, DEFORMATION, SHEAR STRESSES,...

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,...

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...

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,...

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,...

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,...

This memorandum records the proceedings of a four-part seminar series on turbulence and its control sponsored by the Naval Undersea Warfare Center Division, Newport, Rl, during the summer of 1992. The Naval Undersea Warfare Center Division, Newport, RI, organized a four-part seminar series titled Turbulence and Its Control during the summer of 1992 . One seminar was held in June, one in July, and two in August. These seminars were an activity of NUWC's Hydrodynamics Sphere of Excellence, which...

Topics: DTIC Archive, NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI, *SHEAR FLOW, *TURBULENT BOUNDARY LAYER,...

The physical model of a multi-constant elastic material, with consideration of couple-stresses, is studied critically to determine whether it more reasonably represents a 3-constant isotropic material or a 6-constant centro-symmetric cubic crystalline material. A description of a critical shear experiment on the model is presented along with experimental results. A parameter alpha which is definitively related to the question is defined and its value determined on the basis of statical...

Topics: DTIC Archive, RENSSELAER POLYTECHNIC INST TROY NY DEPT OF MECHANICS, *ANISOTROPY, DEFORMATION,...

The scattering of plane compressional waves by a spherical obstacle in an elastic solid, which was investigated by Ying and Truell, is examined further. For a rigid inclusion, the boundary conditions are redefined to take into considera the motion of the inclusion inside the solid. By a proper limiting process, it is shown that the solutions for a rigid insert, a fluid sphere, a cavity, or an obstacle in a fluid, are all derivable from the general results of an elastic inclusion. In each case,...

Topics: DTIC Archive, Pao, Yih-Hsing, MITRE CORP BEDFORD MA, *COMPRESSIBLE FLOW, *ELASTIC SCATTERING,...

It is shown that Weinstein and Whitmire in extending the Thomas precession to an extended rotating disk have made implicit assumptions about integrability, common disk times, and the disk proper frame which have not been justified.

Topics: DTIC Archive, Newburgh, R G, AIR FORCE CAMBRIDGE RESEARCH LABS HANSCOM AFB MA, *RELATIVITY THEORY,...

Analytical expressions are formulated to describe the distribution of shear stresses which arise due to slip and soil flow. The distribution of the shear and normal stresses along the wheel-soil interface is established as a function of slip. The stresses under a towed wheel are also described. Actual measurements of the stresses by means of a special transducer embedded in the wheel are presented and compared to theoretical values. It is found that the agreement is satisfactory. It is...

Topics: DTIC Archive, Sela, Aharon D, ARMY TANK-AUTOMOTIVE CENTER WARREN MI, *SHEAR STRESSES, *ROADWHEELS,...

Erodibility experiments were performed on sediments obtained over a 15-mile stretch of the Lower Passaic River, NJ, to assess remediation options and prioritize remediation as part of the U.S. Environmental Protection Agency's Superfund remedial investigation. A total of 28 sediment cores were extracted from 14 locations on the Passaic River. Measurements of erodibility were performed with U.S. Army Corps of Engineers Sedflume to determine erosion as a function of depth for different shear...

Topics: DTIC Archive, Borrowman, Thomas D, ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS...

Topics: DTIC Archive, Stier, H, GENERAL DYNAMICS CORP POMONA CA POMONA DIV, *SHEAR STRESSES, *RIVETS,...

The test procedures and techniques developed in the studies reported herein provide a means of obtaining photoelastic stress patterns for moving wheel loads at controlled degrees of slip. Sufficient information was developed to compute normal and shear stress distribution on planes in the gelatin foundation within one-fourth inch of the contact surface between the moving wheel load and gelatin, if certain approximations are made. Further study is indicated to accurately define the stress at a...

Topics: DTIC Archive, OHIO RIVER DIV LABS CINCINNATI, *SHEAR STRESSES, *WHEELS, *PHOTOELASTICITY,...

A recent study indicated that the behavior of single-ended dislocation sources contributes to the flow strength of micrometer-scale crystals. In this study 3D discrete dislocation dynamics simulations are used to calculate the effects of anisotropy of dislocation line tension on the strength of single-ended dislocation sources in micrometer-sized volumes with free surfaces, and to compare them with the strength of double-ended sources of equal length. This is done by directly modeling their...

Topics: DTIC Archive, Rao, S I, UES INC DAYTON OH, *CRYSTALS, *DISLOCATIONS, SIMULATION, MODELS, SHEAR...

Explosive experiments were performed to study the critical shear stress beyond the leading edge of shockwaves in aluminum at pressures of 300 and 650 kbar, copper in pressures of 240 and 550 kbar and lead at pressures of 460 kbar. Estimates of this quantity were performed by comparison of experimental data characterizing the decrease in pressure across the leading edge of the shockwave due to unloading with the results of calculation.

Topics: DTIC Archive, Novikov, S A, ARMY FOREIGN SCIENCE AND TECHNOLOGY CENTER CHARLOTTESVILLE VA, *COPPER,...

The results of a study of Ms vs mb characteristics of earthquakes in the Eastern Himalayan region are given in this report. It is shown that in this region some earthquakes occur which have Ms vs mb characteristics similar to explosions, exhibiting low surface wave magnitudes relative to body wave magnitudes, when seen at the reporting stations available to this study. The existence of these anomalous events in certain areas of the world can seriously decrease the effectiveness of the Ms vs mb...

Topics: DTIC Archive, Der, Zoltan A, TELEDYNE GEOTECH ALEXANDRIA VA SEISMIC DATA LAB, *EARTHQUAKES,...

With the use of Karman's integrated momentum equation for the boundary layer and data on the wall-shearing stress and heat transfer in forced-convection flow, a calculation was carried out for the flow and heat transfer in the turbulent free-convection boundary layer on a vertical flat plate. The calculation is for a fluid with a Prandtl number that is close to unity. A formula was derived for the heat-transfer coefficient that was in good agreement with experimental data in the range of...

Topics: DTIC Archive, Eckert, E R, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC, *TURBULENT...

Accurate and efficient tire models for soft soil operations are needed for mobility simulations of wheeled vehicles operating in off-road conditions. The tire model is essential in a vehicle model; the accuracy of the predicted tire forces and moments has a large impact on assessing the vehicle performance, reducing the number of stuck vehicles, avoiding rollovers, and developing advanced control strategies. While finite element method leads to the most detailed tire-soil interaction models,...

Topics: DTIC Archive, VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG, *SOILS, *TIRES, DAMPING, ELASTIC...

This paper presents a geometric Moire optical-based floating-element shear stress sensor for wind tunnel turbulence measurements. The sensor was fabricated using an aligned waferbond/thin-back process producing optical gratings on the backside of a floating element and on the top surface of the support wafer. Measured results indicate a static sensitivity of 0.26 microns/Pa, a resonant frequency of 1.7 kHz, and a noise floor of 6.2/square root Hz.

Topics: DTIC Archive, Horowitz, Stephen, FLORIDA UNIV GAINESVILLE MECHANICAL AND AEROSPACE ENGINEERING,...