Professor H. B. Seed of the University of California and Professor R. V. Whitman of the Massachusetts Institute of Technology visited the U. S. Army Engineer Waterways Experiment Station on 15-16 September 1970 and 26-27 October 1970, respectively, to discuss the earthquake resistance of earth and rock-fill dams. This report contains the records of these visits. (Author)
Topics: DTIC Archive, Cunny,Robert w, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MISS,...
An analytical assessment is made of an apparatus designed for the measurement of the complex shear modulus of viscoelastic materials. It is shown that simple measurements of amplitude ratio and phase angle are sufficient to determine the complex modulus at any point over a wide range of frequency and dynamic strain. Data obtained for butyl rubber and some experimental elastomers are presented.
Topics: DTIC Archive, Adkins, Richard L, AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OH, *VISCOELASTICITY,...
The governing equations for laminated beams are developed by variational methods. The beams are considered to consist of n laminae and n-1 bond layers, where n can be any reasonable number greater than one. The bond thicknesses are assumed to be small in comparison with those of the laminae. The effects of shear strains and direct strains normal to the bending axis in the bond layers are included. Two specific problems are solved: bending under uniform load and buckling of simply supported...
Topics: DTIC Archive, Durlofsky, Harold, STANFORD UNIV CA DEPT OF AERONAUTICS AND ASTRONAUTICS, *AIRFRAMES,...
The model developed in this report provides an exact solution to the equations of motion for an infinite length, axisymmetric, isotropic, forced cylindrical rod. The resulting mechanical stresses are inserted into the governing equations of optical phase sensitivity and the change of refractive index for an optical fiber. This approach produces a closed-form model of light propagation in the fiber when the fiber is subjected to external forcing functions at a definite wavenumber and frequency....
Topics: DTIC Archive, Hull, Andrew J., NAVAL UNDERSEA WARFARE CENTER NEWPORT DIV RI, *FIBER OPTICS, *FINITE...
Simultaneous volume and acoustic velocity measurements have been made to determine the elastic moduli of Salem limestone, Berea sandstone, and Westerly granite. The purpose was to examine differences and similarities between the two measurements. The effects of cyclic loading and water filling were also examined. Significant differences in bulk modulus are observed on pressure release and during crush up. While the volume value of bulk modulus decreases sharply at crush up only a slight knee or...
Topics: DTIC Archive, La Mori, Phillip N, BATTELLE COLUMBUS DIV OH, *MODULUS OF ELASTICITY, *ROCK,...
The Gemini B blast shield is a sandwich construction composed of glass fabric reinforced plastic skins adhesively bonded to aluminum Flexcore. The object of this test was to determine the plate shear strength and the flatwise bare compressive strength of aluminum flexcore as well as the effect of the Flexcore thickness on the plate shear strength.
Topics: DTIC Archive, MCDONNELL CO ST LOUIS MO, *MANNED SPACECRAFT, *METAL PLATES, *ROCKET ENGINES, *SPACE...
The development of a turbulent boundary layer flow through a gap in an isolated wall-mounted roughness element has been studied experimentally. Two flow regions were distinguished downstream of the gap; a distortion region followed by a readjustment region. In the distortion region two counteracting distortion mechanisms were identified, the relative importance of which depended on gap size. Thus flows downstream of large gaps were found to differ significantly from those through small gaps....
Topics: DTIC Archive, Schofield,W H, AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA), *SURFACE ROUGHNESS,...
A load-life model is developed for calculating the fatigue life and reliability of a spur gear mesh. The dynamic capacity of a gear mesh is defined as the tangential load which can be transmitted for one million pinion revolutions with a 90% probability of survival. The model is an extension of the currently accepted Lundberg-Palmgren Rolling Element Bearing Life Model. Limited rolling contact testing of cylindrical samples with and without traction in the contact was accomplished. At a low...
Topics: DTIC Archive, Rumbarger, John H, FRANKLIN INST RESEARCH LABS PHILADELPHIA PA, *HELICOPTERS,...
Topics: DTIC Archive, SKABELUND, DONALD E., UTAH UNIV SALT LAKE CITY DEPT OF PHYSICS,...
A 1/2 x 13 x 25-in. sandwich panel was brazed with sterling Ag + 0. 2% Li brazing alloy. After brazing, the panel was vacuum purged with air ten times. It was cut into specimens and tested at room temperature on a 120,000 lb Baldwin test machine. The results of the mechanical tests are given and photomicrographs showing the extent of oxidation in the brazed fillet are shown. The high strength after exposure was probably due to additional precipitation hardening of the steel during exposure. A...
Topics: DTIC Archive, Farner, H B, GENERAL DYNAMICS CORP POMONA CA POMONA DIV, *STAINLESS STEEL, *BRAZING,...
Topics: DTIC Archive, LOCKHEED AIRCRAFT CORP MARIETTA GA, *TITANIUM ALLOYS, *SHEET METAL, MECHANICAL...
Topics: DTIC Archive, Orr, Raymond L., Bainbridge, Douglas W., CALIFORNIA UNIV BERKELEY MATERIALS RESEARCH...
Topics: DTIC Archive, ThornTthwaite, C W, THORNTHWAITE (C W) ASSOCIATES ELMER NJ LAB OF CLIMATOLOGY,...
This report discusses and describes the concepts and considerations as well as design details of a system capable of storing and retrieving mechanical properties information of metals and reinforced plastics. Included is a description of IBM card layout and codes utilized to store, retrieve, operate on and display the most pertinent numeric and alphabetic information necessary to the description of reported test procedures and results. Examples of graphic and tabular system output are also...
Topics: DTIC Archive, Stulen, F L, BELFOUR ENGINEERING CO SUTTONS BAY MI, *INFORMATION RETRIEVAL,...
The composite boundary layer mouse is an alternative method to the boundary layer velocity profile technique of determining all the pertinent parameters of a turbulent boundary layer. The accuracy of the system in comparison with the profile method was well within experimental tolerances usual with the measurement of boundary layer velocity profiles. The use of the composite system simplified the data reduction which could be performed by any computer, reduced the data reduction time, and...
Topics: DTIC Archive, Roberts, Sean C, MISSISSIPPI STATE UNIV MISSISSIPPI STATE, *BOUNDARY LAYER,...
This paper is concerned with the forced vibrations of case-bonded solid propellant grains. Special attention is paid to the interaction between the thin elastic shell (case) and the thick-walled propellant cylinder. The effects of material damping in the propellant are explored. Frequency-response functions are computed, which can be used for analysis in situations where the loading is arbitrary deterministic or random (stationary).
Topics: DTIC Archive, Henry, L A, COLUMBIA UNIV NEW YORK, *CYLINDRICAL BODIES, *SHELLS(STRUCTURAL FORMS),...
The present state of our knowledge on the mechanical behavior of sapphire is reviewed: Sapphire deforms plastically at temperatures above 900 C, the most common mode of deformation being slip on the basal plan in the 1120 direction. However, under certain conditions, slip may occur on prism planes or twinning may occur. A yield point is often observed. This appears to be related to the multiplication of dislocations by a mechaninism which is controlled by the motion of dislocations through the...
Topics: DTIC Archive, Conrad, H, AEROSPACE CORP EL SEGUNDO CA, *SAPPHIRE, *DEFORMATION, CRYSTAL STRUCTURE,...
The response of a hollow circular cylindrical shell of arbitrary thickness, in either an elastic or a viscoelastic medium, to transient dilatational and shear waves (and their superposition) is presented. The solution is valid within the scope of the linear theory of elasticity or viscoelasticity. The technique for obtaining the solution relies upon (1) the construction of a train of incident pulses from steady-state components, where each pulse represents the time history of the transient...
Topics: DTIC Archive, Nolan, Frank, GRUMMAN AIRCRAFT ENGINEERING CORP BETHPAGE NY, *STRESSES,...
An analytical study of the turbulent mixing of two dissimilar gases in a free shear layer was performed. A simplified method was designed by which closed form expressions could be obtained for the characteristics of such a flow. These included the boundaries of the mixing region, the location of the dividing streamline, the local flow velocities, the local thermodynamic conditions, and the mean rate of energy transport across the shear layer. Although the effects of compressibility and the...
Topics: DTIC Archive, Gray, K E, AERONAUTICAL RESEARCH ASSOCIATES OF PRINCETON INC NJ, *JET MIXING FLOW,...
Ratios of tensile, compressive, shear and bearing properties to corresponding long-transverse tensile properties were computed. Some variations in ratios occur with respect to alloy, temper, thickness, location in thickness, and direction of loading. Groups of ratios for each alloy in the -TX51 tempers were analyzed statistically. Minimum-average values were determined. Using these minimum-average values, together with long-transverse tensile properties from specifications as basis A values and...
Topics: DTIC Archive, ALUMINUM CO OF AMERICA ALCOA CENTER PA, *METAL PLATES, *ALUMINUM ALLOYS,...
Sound pressure fluctuations produced by the turbulent flow of water through 0.494-inch 1D pipe of glass, plastic, and brass were measured at controlled flow rates from 0.65 to 9.6 fps, in the absence of extraneous noise. Hydrophone pickups, pipe wall fluctuations, and pressure differential along the boundary layer were recorded, reduced to quantitative graphic form, and were analyzed by harmonic and numerical methods. Broadband magnitudes were related to Reynolds numbers, pressure spectra were...
Topics: DTIC Archive, NAVY ELECTRONICS LAB SAN DIEGO CA, *PIPES, *TURBULENCE, *FLUID FLOW, NUMERICAL...
Design information on four nickel and cobalt base alloys for inclusion in Military Handbook-5 is presented. The alloys investigated were Rene 41, L-605, Inconel 702, and Incoloy 901. The mechanical properties investigated were tensile, compression, shear, bearing, creep, stress-rupture and fatigue. The raw data generated is presented in this volume.
Topics: DTIC Archive, REPUBLIC AVIATION CORP FARMINGDALE NY, *NICKEL ALLOYS, *COBALT ALLOYS, STRESSES,...
Solutions of the boundary layer equation for an unsteady flow have previously been obtained for only a few boundary conditions such as those which exist in suddenly accelerated or uniformly accelerating flows. In the paper a general solution using the method of successive approximations for an arbitrarily accelerating flow is presented. The solution, which is expressed in an integral form including the acceleration as a chosen function of time, is valid for both two-dimensional and axially...
Topics: DTIC Archive, Odar, Fuat, COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH, *BOUNDARY LAYER,...
An analysis of the stresses in the axial stress-torsion test is presented by considering the gage section as a cylinder undergoing uniform axial deformation with superimposed torsion. Calculation of the stresses requires measurement of the radial deformation and penetration of the plastic region into the notch shoulders. The hydrostatic stress exhibits a peak within the wall of the gage section which increases with decreasing gage length. The fracture strain in room temperature tests increases...
Topics: DTIC Archive, Kuhn, H A, DREXEL INST OF TECH PHILADELPHIA PA DEPT OF METALLURGICAL ENGINEERING,...
Functions of approximation to particular solutions that occur in the ogival radome thermal-stress problem are presented. It was found by numerical comparisons with the generating differential equations that the approximate closed-form solutions display an error range of no more than plus or minus one- half percent. The solutions were derived to gain two major advantages: first, a reduction of analytical complexity lessens the chance of computational error and, second, certain unwieldiness in...
Topics: DTIC Archive, Tate, Manford B, JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB, *RADOMES, *THERMAL...
The research presented in this thesis is on the study of the behavior of the dynamic tangent moduli of polyethylene under large quasi-static deformations. This involved both the determination of the complex shear modulus G* and the complex Youngs modulus E* as a function of longitudinal and torsional strains.
Topics: DTIC Archive, Walsh, James P, BROWN UNIV PROVIDENCE RI DIV OF APPLIED MATHEMATICS, *POLYETHYLENE...
This report presents a systematic analysis of two-dimensional and radial turbulent wall jets using the method of matched asymptotic expansions. The asymptotic solution is carried out in two stages. The first is based on a two parameter expansion of the full Reynolds averaged equations with a k-epsilon model of turbulence quantities. One of the small parameters, gamma, is related to the nondimensional friction velocity, U sub T, defined by the surface shear stress. It is basically a Reynolds...
Topics: DTIC Archive, Melnik,R E, GRUMMAN AEROSPACE CORP BETHPAGE NY RESEARCH AND DEVELOPMENT CENTER,...
While direct and/or large eddy simulations are probably not going to be capable of predicting complex aerodynamic flow field themselves, the methodologies can and should be utilized to solve flow problems that replicate the essential dynamic features of the flill problem. In the near term, this may be the most useful role of such methodologies rather than as a substitute to the currently available RANS-type models. These simulation results can then be used to develop improved closure models for...
Topics: DTIC Archive, Gatski, T. B., NATIONAL AERONAUTICS AND SPACE ADMIN LANGLEY RESEARCH CENTER HAMPTON...
A new analysis of equilibrium boundary layers based on the Schofield and Perry defect law for flow in moderate to strong adverse pressure gradient, is presented. The conditions derived for self-preserving or precise equilibrium boundary layers differ from those given by previous analyses based on the usual velocity defect law. It is shown that nine observed boundary layers on smooth walls conform to these new conditions for equilibrium flow. As the analytical expression for the Schofield and...
Topics: DTIC Archive, Schofield,W H, AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA), *TURBULENT BOUNDARY...
A 'root' vortex forms at the junction of a flat plate and an appendage, creating a three-dimensional separated flow. Time dependent oil film and oil dot visualizations of this turbulent flow have revealed the vortex system and have provided quantitative information on the direction and the magnitude of the shear stress. Two-dimensional LDV (Laser Doppler Velocimetry) mean velocity measurements were made in the separated flow region around the leading edge of the appendage, and these...
Topics: DTIC Archive, Dickinson,Stuart C, DAVID W TAYLOR NAVAL SHIP RESEARCH AND DEVELOPMENT CENTER...
The strength characteristics of quasi-homogeneous, nonisotropic materials are derived from a generalized distortional work criterion. For unidirectional composites, the strength is governed by the axial, transverse, and shear strengths, and the angle of fiber orientation. The strength of a laminated composite consisting of layers of uni-directional composites depends on the strength, thickness, and orientation of each constituent layer and the temperature at which the laminate is cured. In the...
Topics: DTIC Archive, Tsai, Stephen W., PHILCO CORP NEWPORT BEACH CA, *STRESS ANALYSIS, *LAMINATES, *EPOXY...
New interpretations to the results from previously reported air blast-loaded beam tests are derived, based on computations using a modified finite difference large amplitude elastoplastic beam response code which now includes a new strain-rate dependent constitutive model plus associated dynamic material data and revisions to better simulate the physical support conditions, including frictional and rotatory inertia effects.
Topics: DTIC Archive, Huffington,N J , Jr, ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD,...
A series of laboratory experiments were conducted to determine the scouring properties of submerged jets. Five cases were considered: (1) a jet rotating in still water; (2) a fixed jet in a fluid moving parallel to the jet (coflow); (3) a fixed jet in a fluid moving perpendicular to the jet (crossflow); (4) a fixed jet in a fluid moving against the jet (counterflow); and (5) a jet rotating in a moving fluid. In each case, dimensionless equations were developed to estimate the applied shear...
Topics: DTIC Archive, Dellaripa,Frank, NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA, *WATER FLOW, *CLEANING,...
Measurements of surface shear stress magnitude and direction are reported for a three-dimensional, pressure driven, turbulent boundary layer around a wing body junction. Measurements were made using a dual-beam oil film laser interferometer at 56 locations. An iterative procedure was developed which increased the precision of the data extracted from the data records. Skin friction directions computed using a least square error fit were compared to angles obtained from surface oil flows, hot...
Topics: DTIC Archive, Ailinger, K G, VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF AEROSPACE...
The hot deformation response of lamellar colonies of Ti-6Al-4V was established via uniaxial compression testing. For this purpose, samples with a rectangular cross section were cut from single colonies grown using a float-zone technique and then tested at 815 degrees Celsius. Each sample was oriented for single slip along one of seven different slip system in the alpha phase. Measurements of the critical resolved shear stress (CRSS) at yielding and the subsequent flow behavior revealed a strong...
Topics: DTIC Archive, Salem, A A, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND...
The classical problem of lateral buckling of cantilever beams with transverse end-load is re-examined, as an example of a problem fully governed by the intrinsic equations of Kirchhoff's curved beam theory. It is shown that a suitable non-dimensionalization of the differential equations of the problem leads to a straightforward perturbation solution, with leading and second-order terms of the expansion having well-defined differences in physical significance. The equations of a recent extension...
Topics: DTIC Archive, Reissner,E, CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF APPLIED MECHANICS AND...
An experimental study of techniques for modifying the surface shear stress, both mean and fluctuating, in turbulent boundary layers is reported. The surface shear along the test section of a 45.7cm square wind tunnel, with a downstream expansion section, was determined by means of surface-hot-wire-heat-transfer-gauges. Turbulent boundary layers in both zero and adverse pressure gradients were evaluated. The mean and fluctuating surface shear in a zero pressure gradient can be effectively...
Topics: DTIC Archive, Sandborn,V A, COLORADO STATE UNIV FORT COLLINS DEPT OF CIVIL ENGINEERING, *TURBULENT...
Analytical methods for the development of Reynolds stress models in turbulence are reviewed in detail. Zero, one and two equation models are discussed along with second-order closures. A strong case is made for the superior predictive capabilities of second-order closure models in comparison to the simpler models. The central points of the paper are illustrated by examples from both homogeneous and inhomogeneous turbulence. A discussion of the author's views concerning the progress made in...
Topics: DTIC Archive, Speziale, Charles G, INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING...
The procedure describes methods for performing photostress data acquisition, including: the selection, application and calibration of the plastic coating, the acquisition of photostress data using a reflective polarscope, the determination of the directions of principal stresses by the construction of stress trajectories, and the determination of the difference in magnitude of principal stresses (or maximum shearing stress).
Topics: DTIC Archive, ARMY TEST AND EVALUATION COMMAND ABERDEEN PROVING GROUND MD, *STRESSES, *SHEAR...
A theoretical solution is presented for the critical axial-compressive stress of a simply supported curved rectangular panel having a central longitudinal stiffener offering no torsional restraint. The results are presented in the form of computed curves and tables. Because a panel of moderate or large curvature buckles in compression at a stress lower than the theoretical value, a method is suggested to aid in determining the critical stress for use in design.
Topics: DTIC Archive, Schildcrout, Murry, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON DC,...
Experiments were conducted to assess the time-dependent behavior of brittle rock and of rough, unfilled tension joints as a function of stress state and water content at ambient temperature. Quasi-static tests were performed on Westerly granite, Nugget sandstone and Tennessee marble at confining pressures up to 10,000 psi. Creep was measured on granite and sandstone at 1,000 psi, 5, 000 psi and 10,000 psi confining pressure. Finally, creep tests were carried out on granite in uniaxial tension....
Topics: DTIC Archive, Wawersik, Wolfgang R, UTAH UNIV SALT LAKE CITY DEPT OF MECHANICAL ENGINEERING,...
The objective of this study is to develop a better understanding of the stochastic structure of the instantaneous boundary shear processes in open channel flows. This report presents new measurements of some stochastic properties of boundary shear stress taken at points spaced over half the wetted perimeter of a smooth open channel, under conditions of essentially constant aspect ratio and Reynolds number. The instantaneous boundary shear stress was measured with hot-film sensors driven by...
Topics: DTIC Archive, Alonso,Carlos V, SOIL CONSERVATION SERVICE OXFORD MS SEDIMENTATION LAB, *CHANNEL...
This paper is to introduce a formulation, an efficient solution procedure, a microcomputer program, and a graphics routine for an anisotropic symmetrically laminated beam finite element including the effect of shear deformation. The emphasis of the formulation and solution procedure is for simplicity, efficiency, and easy implementation in microcomputers. The element possesses six d.o.f.'s at each of the two nodes: transverse deflection and slope due to bending and shear, respectively; and a...
Topics: DTIC Archive, Yang,T Y, PURDUE UNIV LAFAYETTE IN SCHOOL OF AERONAUTICS AND ASTRONAUTICS,...
A unidirectional fiberglass epoxy composite plate specimen is modelled as a homogeneous transversely isotropic continuum plate medium. Acousto-ultrasonic non-contact input-output characterization by tracing SH waves in the continuum is studied theoretically with a transmitting and a receiving transducer located on the same face of the plate. The single reflection problem at a stress-free plane boundary in a semi-infinite transversely isotropic medium whose isotropic plane is parallel to the...
Topics: DTIC Archive, Williams, James H., Jr., MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL...
A theory is presented for the noise radiated by incompressible boundary-layer transition that occurs on an infinite, rigid flat plate. It is hypothesized that it is the intermittency of the boundary-layer flow within the transition zone that is dominant in noise production. Using Lighthill's analogy, it is shown that dipole, quadrupole, and octupole sources are generated. Under the assumption of low Mach number flow, the power spectral density per unit spanwise width of transition for the...
Topics: DTIC Archive, Lauchle,G C, PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB, *BOUNDARY...
The role of isovalent dopants in the high temperature deformation of GaAs has been studied in the temperature range 550 C to 1150 C. Additions of In, Sb, and B increase the high temperature hardness and the critical resolved shear stress for deformation at a given strain rate and result in lowering the dislocation density of as-grown liquid-encapsulated Czochralski GaAs crystals. Phosphorus, because of its minor influence on the lattice strain, provides little enhancement of the yield stress....
Topics: DTIC Archive, Faber, Katherine T, OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS, *BORON COMPOUNDS,...
Finite element methods for penetration mechanics are developed. A pinball contact-impact algorithm which is easily vectorizable has been implemented on partitioned memory SIMD computers. The pinball algorithm is further extended to problems with friction and erosion; Lagrange and augmented Lagrange multiplier methods, and its convergence have also been studied. Multiple-quadrature elements with hourglass control and physical stabilization and multi-time step integration have also been studied....
Topics: DTIC Archive, Belytschko, Ted, NORTHWESTERN UNIV EVANSTON IL DEPT OF MECHANICAL ENGINEERING,...
Topics: DTIC Archive, Hill, S. G., BOEING AEROSPACE CO SEATTLE WA, *PRIMERS, *COATINGS, *ADHESIVES, THERMAL...
Relative displacement data from high explosive, shallow-buried bursts in rock are combined with relative displacement data from the contained nuclear explosion MIGHTY EPIC. Analysis of these data yields a preliminary, semi- empirical technique for predicting the location, direction and magnitude of relative displacements in rock from contained explosions. This technique is used to make relative displacement predictions for the DIABLO HAWK nuclear blast. (Author)
Topics: DTIC Archive, Blouin, Scott, COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH, *DISPLACEMENT,...
A series of bottom reflection losses are presented in graphical form to show the contribution of shear waves when included in the theoretical acoustic model for bottom sediments. The analysis illustrates the effect of introducing shear waves in the more complicated theoretical model for viscoelastic solids. This memorandum has been prepared because it is believed that the information may be useful in this form to others at NUWC and to a few persons outside NUWC. This memorandum should not be...
Topics: DTIC Archive, Morris,H E, NAVAL UNDERSEA WARFARE CENTER SAN DIEGO CALIF, *UNDERWATER ACOUSTICS,...
