Progress is reviewed with emphasis on a model of stress intensity factors in dynamic punch test. The specimen is assumed to be initially at rest and the projectile is rigid. Impact of the rigid projectile is modeled by a constant velocity condition on the impact surface. Three support geometries are considered for each specimen geometry: a free back surface, a fixed back surface, and a two dimensional punch. Analytical approximations for the stress intensity factor history are given for short...

Topics: DTIC Archive, Mason, J. J., NOTRE DAME UNIV IN DEPT OF AEROSPACE AND MECHANICAL ENGINEERING,...

In recent years, increasing interest has centered on the development of reliable and computationally inexpensive a posteriori error estimates for finite element computations. Such estimates can provide some, often critically important, information about the accuracy and reliability of the computed solution as a model of the behavior of the physical phenomena under study. At the same time it has become widely accepted that these estimates also constitute a basic tool in the construction of...

Topics: DTIC Archive, Rheinboldt,W C, PITTSBURGH UNIV PA INST FOR COMPUTATIONAL MATHEMATICS AND...

The method of coupled azimuthal potentials (CAP) was applied to a waveguide model of an axially symmetric engine inlet to analyze the fields in the region where the front face of the engine terminates the waveguide. Appropriate boundary conditions were derived and the finite element method was used to solve for the potentials. The Lagrangian of the CAP equations does not provide for the enforcement of Neumann boundary conditions. This prevents exact implementation of the correct boundary...

Topics: DTIC Archive, Cooper,Thomas Gerard, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF...

A user-defined subroutine has been developed to implement special 2-D and 3-D layered continuum elements in the commercial finite element program ABAQUS. These elements are specially configured to accurately predict interface stresses in adhesively bonded joints and are formulated using the hybrid stress technique to explicitly enforce stress equilibrium throughout the element domain and stress continuity conditions at layer interfaces. This report details the use of developed special 'adhesive...

Topics: DTIC Archive, Saether, Erik, ARMY RESEARCH LAB WATERTOWN MA MATERIALS DIRECTORATE, *COMPUTER...

This volume contains the papers that were presented at the 1995 MRS Fall Meeting in Symposium Q, entitled 'Fracture: Instability Dynamics, Scaling, and Ductile/Brittle Behavior.' The purpose of the symposium was to bring together the many communities that investigate the fundamentals of fracture, with special sessions on the ductile/brittle transition, fracture at interfaces, fracture in ceramics and composites, dynamic instabilities in crack propagation, and fractals and scaling in fracture....

Topics: DTIC Archive, Blumberg Selinger, Robin L., MATERIALS RESEARCH SOCIETY PITTSBURGH PA, *SYMPOSIA,...

This report describes an analysis of the static aeroelastic response of an aircraft with asymmetrical wing planforms representing combat damage. The analysis was performed using the MSC/NASTRAN Aeroelastic Code. Structural and aerodynamic models are based on the finite element approach and are created independently for both the damaged and undamaged cases. Fuselage, wings (with aileron), stabilators, an vertical wings (with rudders) are considered as lifting and control surfaces in the...

Topics: DTIC Archive, Woo, Jong-Ho, ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD, *MODELS, *AEROELASTICITY,...

A hybrid finite element cum T-matrix technique is introduced for the analysis of problems involving acoustic wave scattering by shells of revolution immersed in water. The concept of a mechanical impedance or receptance is used from the theory of vibrations to provide a relationship between the velocity of the shell surface and the pressure acting upon it. This relationship is introduced in the Helmholtz integral relations for the incident and scattered fields and a T-matrix for the scattering...

Topics: DTIC Archive, Eswaran,Kumar, OHIO STATE UNIV COLUMBUS DEPT OF ENGINEERING MECHANICS, *ACOUSTIC...

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In order to evaluate whether high strength concrete with recycled aggregate can be applied for concrete structures, flexural loading tests of reinforced recycled concrete members are to be carried out. The results of this test programme to study the use of recycled coarse aggregate in high strength 40 N/mm2 concrete are to be described. The recycled coarse aggregates are mainly produced from various concrete members of a building structure. The high strength concrete by using different...

Topics: High Strength Concrete, Flexural Strength, Recycled Aggregates, Finite Element Analysis, Linear...

The monthly Literature Review, a subjective critique and summary of the literature, consists of two to four review articles each month, 3,000 to 4,000 words in length. The purpose of this section is to present a 'digest' of literature over a period of three years. Planned by the Technical Editor, this section provides the DIGEST reader with up-to-date insights into current technology in more than 150 topic areas. Review articles include technical information from articles, reports, and...

Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON D C SHOCK AND VIBRATION INFORMATION CENTER, *VIBRATION,...

The finite element-alternating method is used to determine stress intesity factors along the periphery of a part-elliptical crack emanating from a fastener hole in a finite-thickness plate. The method performs a sequence of iterations between an analytic solution for an elliptical crack embedded in an infinite solid and a finite element solution for a finite-thickness uncracked plate with a fastener hole to obtain the stress field near the crack, the stress intensity factor and the crack...

Topics: DTIC Archive, Smith, F. W., COLORADO STATE UNIV FORT COLLINS DEPT OF MECHANICAL ENGINEERING,...

A rational function is presented for approximating the function f(z) = coth z - 1/z that appears in several exponentially fitted or weighted finite difference and finite element methods for convection-diffusion problems. The approximation is less expensive to evaluate than f(z) and provides greater accuracy than the doubly asymptotic approximation when z = 0(1).

Topics: DTIC Archive, Flaherty, Joseph E, AIR FORCE OCCUPATIONAL MEASUREMENT CENTER RANDOLPH AFB TX,...

Modern numerical methods for the optimization of large discretized systems are now well developed and highly efficient in the case of thin walled elastic structures modeled by finite elements. However, this is not yet true for structures whose components are subject simultaneously to bending and extension loads. In this paper, the idea of Generalized Optimality Criterion (GOC), set forth in previous final scientific reports for bar, membrane and pure bending elements, is extended to deal with...

Topics: DTIC Archive, Fleury,Claude, LIEGE UNIV (BELGIUM) LABORATOIRE DE TECHNIQUES AERONAUTIQUES ET...

Numerical methods for the analysis of the elastic-plastic fracture problem using a special finite element technique are presented. A brief description of some concepts in elastic-plastic fracture mechanics and of the finite element method is followed by the formulation procedure of the stiffness matrix using eight-noded quadrilateral isoparametric elements. After a terse discussion of the initial stress method, the procedure of computation is extended in the analysis by using an incremental...

Topics: DTIC Archive, Loo,F T C, CLARKSON COLL OF TECHNOLOGY POTSDAM N Y DEPT OF MECHANICAL AND INDUSTRIAL...

This study addressed the effect of clearances between the tube and its support and the effect of support stiffness on the muzzle motions produced when a weapon is fired. A small-scale test weapon was designed, fabricated, and tested during the study. The test weapon included provisions for changing the clearance between the tube and the tube support sleeve and for changing support stiffness. Breech eccentricity and lubrication between sliding surfaces were also varied. A series of experiments...

Topics: DTIC Archive, Cox,P A, SOUTHWEST RESEARCH INST SAN ANTONIO TX, *FINITE ELEMENT ANALYSIS, *GUN...

A vortex lattice code was developed to generate potential flow solutions over three dimensional bodies. An approximate boundary layer technique is incorporated to allow the calculation of the line separation. The separated vortex sheets are modeled in terms of a vortex grid which is convected with the flow. Special conditions at separation determine the strength of nascent vorticity. Viscous inviscid interaction in three dimensions allows the accurate prediction of the line of separation and...

Topics: DTIC Archive, Telionis,Demetri P, VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF...

Until recently, the one-parameter singular expression for stresses near a crack-tip was widely thought to be sufficiently accurate over a reasonable region for any geometry and loading conditions. This view has been fast changing due to the growing evidence that the inclusion of higher order terms can significantly affect the solution, particularly under certain biaxial loading conditions. In this context, the present paper examines the strain energy density criterion for fracture, and the...

Topics: DTIC Archive, Wong,A K, AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA), *CRACKING(FRACTURING),...

Equilibrium problems for many physical systems are modelled by parameter dependent nonlinear equations F(z,lambda) =0. Under fairly general conditions the set of solutions (z, lambda) of this equation forms a differentiable manifold, and, typically in applications, interest centers not so much on computing a few solutions but rather on analysing the form and special features of this manifold. This paper identifies some of the sources of the errors which are necessarily arising in such a...

Topics: DTIC Archive, Rheinboldt, Werner C, PITTSBURGH UNIV PA INST FOR COMPUTATIONAL MATHEMATICS AND...

In Very Large Scale Integration (VLSI) chips, metal migration(MM) is an important problem from the reliability standpoint. Furthermore, as the feature size is scaled down, MM becomes an even greater problem because of the higher current densities that would exist in the power and ground busses. Because of the complexity of VLSI power busses, there exists a need for a computer-aided design tool to correctly predict the likely failure site(s). This thesis deals with a primitive splitting...

Topics: DTIC Archive, Cha, Hungse, ILLINOIS UNIV AT URBANA DEPT OF ELECTRICAL ENGINEERING, *MIGRATION,...

The goal of this thesis was to develop and validate a set of microcomputer programs using, in part, a previously written finite-element algorithm to analyze the perturbation of an incident electromagnetic field as it penetrates a missile radome. An interactive program was developed to design the radome structure using aerodynamic shaping functions and provide structure and material files as input to the finite-element code. A second program was developed to use the spherical harmonic expansion...

Topics: DTIC Archive, Vince, Robert J, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *MODELS, *GUIDED MISSILE...

A finite element model is developed for structural analysis of axisymmetric geometries with surface contact. The contact occurs when small gaps exist between adjacent parts of the structure and these gaps are closed during the loading cycle. In the model, this phenomenon is simulated by special gap finite elements. Originally, the gap elements have relatively low stiffness, and as surface contact is obtained, the stiffness matrix of these elements is modified to simulate very stiff response in...

Topics: DTIC Archive, Zak, Adam R, ZAK TECHNOLOGIES INC CHAMPAIGN IL, *VISCOPLASTICITY, MATERIALS,...

The authors' recent result on the phase difference for one-dimensional problems in numerically evaluated and discussed in the context of other work directed to this topic. It is shown that previous error estimates in integral norm are of nondispersive character but hold for medium or high wavenumber on extremely refined mesh only. On the other hand, recently proven error estimates on normalized mesh contain a pollution term. With certain assumptions on the exact solution, this term is of the...

Topics: DTIC Archive, Ihlenburg, Frank, MARYLAND UNIV COLLEGE PARK INST FOR PHYSICAL SCIENCE AND...

This project addressed durability and damage and fracture development and monitoring in adhesive composite joints for aerospace structural applications. Experimental and theoretical studies of static and fatigue behavior of single lap adhesive joints were performed on joints with unidirectional (UD) and cross-ply (CP) adherends made from a graphite-epoxy composite and an adhesive used in the Air Force. Joints with and without deliberately introduced cracks and delaminations were analyzed....

Topics: DTIC Archive, Dzenis, Y A, NEBRASKA UNIV LINCOLN, *NONDESTRUCTIVE TESTING, *COMPOSITE MATERIALS,...

One of the last frontiers of structural dynamics is mid-frequency vibration analysis of complex structures. In the low-frequency range, finite element analysis (FEA) is well established as the standard method, However, as the frequency of vibration increases, the cost of FEA becomes prohibitive due to the necessary refinement of the finite element mesh to capture the shorter wavelength of vibration. Furthermore, the system response becomes sensitive to small parameter variations at higher...

Topics: DTIC Archive, Pierre, Christophe, MICHIGAN UNIV ANN ARBOR DEPT OF MECHANICAL ENGINEERING,...

In this study, a systematic investigation of the fretting fatigue behavior of nickel alloy, IN-100 was carried out. The study includes both experimental work and the corresponding analysis of the contact conditions, and the latter is accomplished using the finite element method. Fretting fatigue tests were performed over a wide range of axial stresses to examine both low and high cycle fretting fatigue under constant contact load and the influence of different pad geometries was also explored....

Topics: DTIC Archive, Madhi, Elhoucine, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS...

The Durability Patch Program addresses the repair and life enhancement of nuisance cracks which have been induced into secondary structure by resonant high cycle fatigue from aerovibroacoustics. For this type of damage, safety of flight concerns are virtually non-existant, but maintenance and repair costs are high. Conventional repair techniques consist of mechanically fastened, single sided doublers. For significant static in-plane loads and/or for significant vibration levels due to...

Topics: DTIC Archive, Rogers, Lynn C, CSA ENGINEERING INC MOUNTAIN VIEW CA, *CRACK PROPAGATION,...

Mitigation techniques are currently being sought to ensure public safety in the event of intentional or accidental explosions. Building material fragmentation is a major cause of human injury during such events. Use of concrete masonry walls is a common method of building construction. Concrete masonry provides a fast inexpensive way to construct buildings of various heights; however, these walls are extremely vulnerable to blast pressure resulting in collapse, fragmentation and severe injury...

Topics: DTIC Archive, Moradi, Lee G, ALABAMA UNIV IN BIRMINGHAM SCHOOL OF ENGINEERING, *EXPLOSION EFFECTS,...

Experimental observations on tensile specimens in [1] indicated that the growth of initially present processing induced voids in a nickel based single crystal superalloy played a significant role in limiting creep life. Also, creep tests on single crystal superalloy specimens typically show greater creep strain rates and/or reduced creep life for thinner specimens than predicted by current theories. In order to quantify the role of void growth in single crystals in creep loading, we have...

Topics: DTIC Archive, UNIVERSITY OF NORTH TEXAS DENTON, *SINGLE CRYSTALS, *SUPERALLOYS, CREEP, CREEP TESTS,...

The objective of the project is to investigate the thermo-mechanical behavior of engineered shape memory polymer (SMP) materials for use as composite reconfigurable skin systems in morphing aircraft applications. An anisotropic, reconfigurable skin based on selective heating of a cellular SMP material was designed and investigated to understand its material characteristics. The engineered skin material is made of a cellular structure filled with a variable stiffness material, such as honeycomb...

Topics: DTIC Archive, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AEROSPACE SYSTEMS DIR, *AIRFRAMES,...

This paper presents the Modified Conjugate Residual (MCR) Method, a stabilized version of Luenberger's Method of Conjugate Residuals, for solving large sparse systems of linear equations. This iterative method has special significance when the system is not positive definite so that methods like Conjugate Gradients are inapplicable. In the special case when the system is positive definite, MCR reduces to one of the family of general conjugate gradient methods discussed by Hestenes.

Topics: DTIC Archive, Chandra,R, YALE UNIV NEW HAVEN CONN DEPT OF COMPUTER SCIENCE, *PARTIAL DIFFERENTIAL...

The Finite Element Methods was used to solve the nonlinear electron plasma equations for the System-Generated Electromagnetic Pulse boundary layer in one spatial dimension. These equations were solved in distance-velocity phase space using a rectangular finite element mesh. Linear approximations were used for both the trial and weight functions for each element. The advection terms in the Vlasov plasma equation were treated with the Heinrich upwinding technique. The time integration was...

Topics: DTIC Archive, Gaudet,John A, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING,...

Unconstrained variational formulation has been applied to initial, boundary value problems previously with some numerical success. More recently, an adjoint bilinear variational principle has also been developed for initial and initial-boundary value problems which requires that the initial conditions be satisfied exactly and hence is a constrained variational formulation. This present report compares the numerical results of these two variational formulations for the case of a stress wave...

Topics: DTIC Archive, Wu,Julian J, ARMY ARMAMENT RESEARCH AND DEVELOPMENT COMMAND WATERVLIET NY LARGE...

The principal goal of the study was to evaluate an analytical procedure for predicting progressive collapse in damaged complex structures. A structure was modeled for analysis by the finite element method using relatively large, simple elements. There was little or no refinement of mesh size in areas of initial damage or damage propagation. A method was developed for determining and applying allowable stresses to help compensate for the absence of model detail. Stress results of a finite...

Topics: DTIC Archive, Riggs,Gregory Edward, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH, *FINITE ELEMENT...

In this paper a simple crack model is proposed and the behavior of this crack under stress is explored. The crack consists of an ordinary Griffith crack, but on either side of this crack, at a distance w, exist two slip planes that are parallel to the crack plane. It is assumed that slip can only take place on these two planes. Elsewhere the material is elastic. When w is set equal to zero the crack becomes a Bilby-Cottrell-Swinden crack. This crack model simulates in a simple way the elastic...

Topics: DTIC Archive, Weertman, J, NATIONAL BUREAU OF STANDARDS BOULDER CO, *CRACKS, *FINITE ELEMENT...

The results of several investigations dealing with the design technology of advanced composites are reported. Experimental work was conducted on Hercules graphite/epoxy prepreg in two forms: AS1/3501-6 unidirectional tape and A370-5H/3501-6 fabric. The investigations examine damage tolerance of cylinders, shear buckling, unsymmetric laminates, aeroelastic behavior, and several other topics. In addition, the major accomplishments and benefit of this five year program are highlighted. (Author)

Topics: DTIC Archive, Mar,James W, MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF AERONAUTICS AND...

A new four-node (non-flat) general quadrilateral shell element for geometric and material static and dynamic nonlinear analysis is presented. The element is formulated using three-dimensional continuum mechanics theory and it is applicable to the analysis of thin and thick shells. The formulation of the element and the solutions to various test and demonstrative example problems are presented and discussed.

Topics: DTIC Archive, Bathe, K J, MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF MECHANICAL ENGINEERING,...

It is shown that the adjoints of a spline based approximation scheme for delay equations do not converge strongly. Keywords: Delay equation, Spline approximation.

Topics: DTIC Archive, Burns, John, INSTITUTE FOR COMPUTER APPLICATIONS IN SCIENCE AND ENGINEERING HAMPTON...

This thesis is based on research conducted at the newly constructed Aeronautics and Astronautics Control Sciences Laboratory at the University of Washington. The set up of the UWAA 20-bay planar truss is described, and is based upon a simular experimental test bed at the United States Air Force Academy. Validation of existing open loop finite element models of the truss in the cantilevered configuration was conducted for this research. The formulation of non-linear and approximate linear models...

Topics: DTIC Archive, Shepherd, Michael J, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH, *SPACE BASED,...

Analytical and experimental validation of methods to predict structural vibration and radiated noise is presented in this paper. A rectangular box excited by a mechanical shaker was used as a vibrating structure. Combined finite element method (FEM) and boundary element method (BEM) models of the apparatus were used to predict the noise radiated from the box. The FEM was used to predict the vibration, and the surface vibration was used as input to the BEM to predict the sound intensity and...

Topics: DTIC Archive, Seybert, A F, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS...

The theoretical research performed under the auspices of this grant has played a central role in the investigation of optical and magneto-optical properties of semiconductor heterostructures. There are two major developments to report. One is that the method of finite elements has been proved to be a very effective, flexible, and powerful approach for the calculation of energy levels in semiconductor superlattices and quantum well structures. The second is the method of tight-binding which...

Topics: DTIC Archive, Ram-Mohan, L R, WORCESTER POLYTECHNIC INST MA DEPT OF PHYSICS, *OPTICAL PROPERTIES,...

A finite element numerical model is presented which simulates vibrations in and around inclusions in viscoelastic fluids excited by a sinusoidal pressure wave or pulse generated by noisy machinery. Stress transfer processes are investigated and regions of highest energy dissipation identified. The model simulates the time evolution of stress generation in and around inclusions in the viscoelastic plastic fluid in three space dimensions. Fluid composites recommended for their power dissipative...

Topics: DTIC Archive, Wendlandt, B, MATERIALS RESEARCH LABS ASCOT VALE (AUSTRALIA), *VISCOUS FLOW,...

This report discusses the integration of a novel finite element for analyzing composite material structures into a commercially available finite element software package. This element is a constitutive equation based formulation that predicts individual layer strains and stresses in a computationally efficient manner. Implementing this element into a commercial code will improve its efficiency for predicting the structural response of composite material structures. The work discussed in this...

Topics: DTIC Archive, Jones, Mark, SOUTHWEST RESEARCH INST SAN ANTONIO TX, *SOFTWARE ENGINEERING,...

We have continued our work on developing the fundamental simulation technologies needed for battlefield trauma treatment training software. New approaches to including haptic feedback for trauma surgery have been created through the integration of robotics and physics-based tissue modeling into a real-time simulation architecture. We have demonstrated interactive models representing both flexible and rigid structures, are continuing to develop techniques for volume deformation and surface...

Topics: DTIC Archive, Higgins, Gerald A, HIGH TECHSPLANATIONS INC ROCKVILLE MD, *COMPUTER PROGRAMS,...

The onset and growth of delaminations in unnotched graphite-epoxy laminates is described quantitatively. These laminates, designed to delaminate at the edges under tensile loads, were tested and analyzed. Delamination growth and stiffness loss were monitored nondestructively. Laminate stiffness decreased linearly with delamination size. The strain energy release rate, G, associated with delamination growth, was calculated from two analyses. A critical G for delamination onset was determined,...

Topics: DTIC Archive, O'Brien, T. K., NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY...

The low velocity impact response of graphite/epoxy laminates is investigated theoretically and experimentally. A 9-node isoparametric finite element in conjunction with an empirical contact law was used for the theoretical investigation. Flat laminates subjected to pendulum impact were used for the experimental investigation. Theoretical results are in good agreement with strain gage experimental data. The collective results of the investigation indicate that the theoretical procedure describes...

Topics: DTIC Archive, Tan, T. M., PURDUE UNIV LAFAYETTE IN COMPOSITE MATERIALS LAB, *IMPACT, *STRESS WAVES,...

The adequacy of a structure can only be realistically determined if it is assessed with sound knowledge of the loads that are likely to be applied to that structure. Therefore, methods for evaluating hydrodynamic loads on ships have been reviewed in order to assess their applicability to RAN ships. The different methods are used at various stages of design or analysis dependant upon the amount of time and information available to the designer/analyst. Methods for calculating still water loads...

Topics: DTIC Archive, Phelps, B. P., AERONAUTICAL AND MARITIME RESEARCH LAB MELBOURNE (AUSTRALIA),...

This effort exploits the unique physical and electrical characteristics of carbon nanotubes (CNTs) for field emission applications. Carbon nanotube field emission devices are designed, fabricated, and tested. Two reliable CNT synthesis methods, microwave plasma enhanced chemical vapor deposition (MPE-CVD) and thermal chemical vapor deposition (T-CVD), are developed. The physical properties of the resulting CNTs are analyzed using Raman spectroscopy and Scanning electron microscopy (SEM) and...

Topics: DTIC Archive, AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND...

This research, funded by the Department of Defense via the Research and Education Program for Historically Black Colleges and Universities and Minority-Serving Institutions (HBCU/MI), was conducted at the Applied Mechanics and Materials Research Laboratory, Howard University, Washington, DC from May 1, 2011 through October 31, 2014. The overall objective of the project is to develop and implement robust simulation-based strategies for notch root analysis and fatigue life prediction that account...

Topics: DTIC Archive, HOWARD UNIV WASHINGTON DC, *CRACKING(FRACTURING), *FATIGUE LIFE, *NOTCH TOUGHNESS,...

'SPAN' is a computer program for static and dynamic analysis of stiffened plates and grillages. This addendum contains a precis of R630, plus additional information on computing times, control-cards and permissible problem size. It may be regarded as superseding that document for the conversant SPAN user.

Topics: DTIC Archive, Mitchell,G C, NAVAL CONSTRUCTION RESEARCH ESTABLISHMENT DUNFERMLINE (SCOTLAND),...

A constitutive model was recently proposed to describe flow and damage in rapidly loaded structural materials. Its finite element implementation is given in the present work, with numerical results to be reported in a subsequent work. One important feature is that the finite element formulation is 'consistent' in that the damage and flow strains are approximated in the same was as the corresponding parts of the total strain. A second important feature is that certain interelement continuity...

Topics: DTIC Archive, Nicholson,David W, NAVAL SURFACE WEAPONS CENTER SILVER SPRING MD, *METALS, *DAMAGE,...

A hybrid finite-element numerical model was used to calculate harbor resonance, relative to that for existing conditions, for proposed non-Federal dredging adjacent to East Channel in the Port of Los Angeles. The numerical model yields convergent solutions for harbors of arbitrary shape and variable depth. The response of East Channel to long-period wave excitation was calculated over the 60- to 600-sec range for each plan. Wave-height amplification was similar at periods less than 200 sec;...

Topics: DTIC Archive, Outlaw,Douglas G, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS HYDRAULICS...