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Consistent linearization method for finite-element analysis of viscoelastic materials

Description: A method of formulating material models for viscoelastic analysis using the finite-element method is presented. The method, named consistent linearization, includes the influence of creep in the material stiffness in a theoretically ideal manner. This method has been applied to the linear viscoelastic analysis of graphite subject to irradiation. Previously, using the initial strain method, short time steps had been required to avoid a numerical instability associated with the rapid transient cr… more
Date: May 1, 1983
Creator: Smith, P.D. & Pelessone, D.
Partner: UNT Libraries Government Documents Department
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Developing natural convection in a fluid layer with localized heating and large viscosity variation

Description: Numerical simulations and laboratory experiments are used to elucidate aspects of transient natural convection in a magma chamber. The magma chamber is modeled as a horizontal fluid layer confined within an enclosure of square planform and heated from below by a strip heater centered on the lower boundary of the enclosure. The width of the strip heater and the depth of the fluid layer are one-fourth of the layer width. Corn syrup is used as the working fluid in order to approximate the large vi… more
Date: January 1, 1991
Creator: Hickox, C.E. & Chu, Tze Yao.
Partner: UNT Libraries Government Documents Department
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Conductor stress analysis for the mirror fusion test facility (MFTF) magnet system

Description: This report describes the analysis performed to establish the sensitivity of winding gaps on conductor hoop stress. Since this task was a follow-on to the program that confirmed the structural integrity of the MFTF magnet case, jacket, and shield system, every effort was made to utilize analysis methods and tools developed during that program. The large, 5000 degree of freedom GDSAP model developed during that program which was used extensively throughout this analysis task is presented. This m… more
Date: March 1, 1979
Creator: Baldi, R. W. & Poniktera, C. D.
Partner: UNT Libraries Government Documents Department
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Transportation system impact limiter design using rigid polyurethane foam

Description: Techniques used to apply the finite element method to the analysis of rigid polyurethane foam that is confined by a thin, ductile metallic skin were investigated. The initial investigation covered the analysis of a simple geometry and loading condition of constrained and unconstrained foam using the constitutive relationships implied in the ''Elastic-Plastic'' and ''Crushable Foam'' material models in HONDO II and DYNA2D/3D. The final investigation consisted of the analysis of a series of tests… more
Date: June 1, 1985
Creator: Wellman, G. W.
Partner: UNT Libraries Government Documents Department
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Graphite targets at LAMPF

Description: Rotating polycrystalline and stationary pyrolytic graphite target designs for the LAMPF experimental area are described. Examples of finite element calculations of temperatures and stresses are presented. Some results of a metallographic investigation of irradiated pyrolytic graphite target plates are included, together with a brief description of high temperature bearings for the rotating targets.
Date: January 1, 1983
Creator: Brown, R. D. & Grisham, D. L.
Partner: UNT Libraries Government Documents Department
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Even- and odd-parity finite-element transport solutions in the thick diffusion limit

Description: We analyze the behavior of odd-parity continuous finite-element methods (CFEMs) for problems that contain diffusive regions. We find that each of these method produces a solution that, to leading order inside diffusive regions, satisfies a discretization of the diffusion equation. We find further that these leading-order solutions satisfy boundary conditions that can lead to large errors in the interior solution. We recognize, however, that we can combine an odd-purity CFEM solution and an even… more
Date: January 7, 1991
Creator: Adams, M.L.
Partner: UNT Libraries Government Documents Department
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Generalized multidemensional propagation velocity equations for pool-boiling superconducting windings

Description: Several finite difference, finite element detailed analyses of propagation velocities in up to three dimensions in pool-boiling windings have been conducted for different electromagnetic and cryogenic environments. Likewise, a few full scale simulated winding and magnet tests have measured propagation velocities. These velocity data have been correlated in terms of winding thermophysical parameters. This analysis expresses longitudinal and transverse propagation velocities in the form of power … more
Date: September 1, 1984
Creator: Christensen, E.H. & O'Loughlin, J.M.
Partner: UNT Libraries Government Documents Department
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FSI analysis of piping systems under seismic excitation

Description: A formulation which accounts for fluid-structure interaction of piping system under seismic excitation is presented. The governing equations of the fluid and the structure to model the pipe are stated. Using the finite element method the discretized equations are obtained. A transformation procedure for proper assembly of matrices is introduced. A solution algorithm is described. 9 refs., 2 figs.
Date: January 1, 1991
Creator: Uras, R.A.; Ma, D.C.; Chang, Yao W. (Argonne National Lab., IL (USA)) & Liu, Wing Kam (Northwestern Univ., Evanston, IL (USA). Dept. of Mechanical Engineering)
Partner: UNT Libraries Government Documents Department
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Structural analysis of the magnet system for Mirror Fusion Test Facility (MFTF). Addendum I

Description: The stress analysis refinement of the MFTF magnet system using GDSAP (General Dynamics Structural Analysis Program) and NASTRAN finite element computer models has been completed. The objective of this analysis was to calculate a more refined case and jacket stress distribution. The GDSAP model was refined in the minor radius area to yield a more detailed prediction of the stress distributions in critical areas identified by the previous analysis. Modifications in the case plate thickness (from … more
Date: September 1, 1979
Creator: Loss, K.R. & Wohlwend, J.W.
Partner: UNT Libraries Government Documents Department
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Quasilinear simulation of auroral kilometric radiation by a relativistic Fokker-Planck code

Description: An intense terrestrial radiation called the auroral kilometric radiation (AKR) is believed to be generated by cyclotron maser instability. We study a quasilinear evolution of this instability by means of a two-dimensional relativistic Fokker-Planck code which treats waves and distributions self-consistently, including radiation loss and electron source and sink. We compare the distributions and wave amplitude with spacecraft observations to elucidate physical processes involved. 3 refs., 1 fig.
Date: January 1, 1991
Creator: Matsuda, Y.
Partner: UNT Libraries Government Documents Department
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Thermal shield support degradation in pressurized water reactors

Description: Damage to the thermal shield support structures of three pressurized water reactors (PWRs) due to flow-induced vibrations was recently discovered during refueling. In two of the reactors, severe damage occurred to the thermal shield, and in one reactor the core support barrel (CSB) was damaged, necessitating extended outages for repairs. In all three reactors, several of the thermal shield supports were either loose, damaged, or missing. The three plants had been in operation for approximately … more
Date: January 1, 1986
Creator: Sweeney, F. J. & Fry, D. N.
Partner: UNT Libraries Government Documents Department
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Nonliner analysis techniques for use in the assessment of high-level waste storage tank structures

Description: Reinforced concrete in combination with a steel liner has had a wide application to structures containing hazardous material. The buried double-shell waste storage tanks at the US Department of Energy's Hanford Site use this construction method. The generation and potential ignition of combustible gases within the primary tank is postulated to develop beyond-design-basis internal pressure and possible impact loading. The scope of this paper includes the illustration of analysis techniques for t… more
Date: September 1, 1991
Creator: Moore, C. J.; Julyk, L. J.; Fox, G. L. (Westinghouse Hanford Co., Richland, WA (United States)) & Dyrness, A. D. (Advent Engineering Services, Inc., San Ramon, CA (United States))
Partner: UNT Libraries Government Documents Department
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Analysis of spherical geometry finite element transport solutions in the thick diffusion limit

Description: An asymptotic analysis if performed on a family of discontinuous finite element methods (DFEMs) for spherical geometry transport. It is found that transport methods of this type transition into discrete versions of the spherical geometry diffusion equation in the thick diffusion limit with boundary conditions that may, in general, be inaccurate. A linear DFEM method has been designed such that its asymptotic diffusion boundary conditions are accurate. In a related development, the asymptotic di… more
Date: January 15, 1991
Creator: Palmer, T.S. (Michigan Univ., Ann Arbor, MI (USA). Dept. of Nuclear Engineering) & Adams, M.L. (Lawrence Livermore National Lab., CA (USA))
Partner: UNT Libraries Government Documents Department
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Transient two-dimensional flow in porous media

Description: The transient flow of an isothermal ideal gas from the cavity formed by an underground nuclear explosion is investigated. A two-dimensional finite element method is used in analyzing the gas flow. Numerical results of the pressure distribution are obtained for both the stemming column and the surrounding porous media.
Date: September 14, 1979
Creator: Sharpe, L. Jr.
Partner: UNT Libraries Government Documents Department
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Time finite element methods for large rotational dynamics of multibody systems

Description: Weak formulations in Analytical Dynamics are developed, paralleling the variational methods in elastostatics, and including a fundamental yet novel approach for treating constraints (both holonomic and nonholonomic). A general three field approach is presented, in which the momentum balance conditions, the compatibility conditions between displacement and velocity, the constitutive relations and the displacement and momentum boundary conditions are all enforced in weak form. A primal, or kinema… more
Date: January 1, 1990
Creator: Mello, F. J.; Borri, M. & Atluri, S. N.
Partner: UNT Libraries Government Documents Department
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Study and full-scale test of a high-velocity grade-crossing simulated accident of a locomotive and a nuclear-spent-fuel shipping cask

Description: This report described structural analyses of a high-speed impact between a locomotive and a tractor-trailer system carrying a nuclear-spent-fuel shipping cask. The analyses included both mathematical and physical scale-modeling of the system. The report then describes the full-scale test conducted as part of the program. The system response is described in detail, and a comparison is made between the analyses and the actual hardware response as observed in the full-scale test. 34 figures.
Date: February 1, 1983
Creator: Huerta, M. & Yoshimura, H.R.
Partner: UNT Libraries Government Documents Department
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Seismic analysis of liquid metal reactor piping systems

Description: To safely assess the adequacy of the LMR piping, a three-dimensional piping code, SHAPS, has been developed at Argonne National Laboratory. This code was initially intended for calculating hydrodynamic-wave propagation in a complex piping network. It has salient features for treating fluid transients of fluid-structure interactions for piping with in-line components. The code also provides excellent structural capabilities of computing stresses arising from internal pressurization and 3-D flexu… more
Date: January 1, 1987
Creator: Wang, C. Y.
Partner: UNT Libraries Government Documents Department
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Assessment of stress-strain data suitable for finite-element elastic--plastic analysis of shipping containers

Description: Stress-strain data which describes the influence of strain rate and temperature on the mechanical response of materials presently being used for light water reactor fuel shipping containers have been assembled. Selection of data has been limited to that which is suitable for use in finite-element elastic--plastic analysis of shipping containers (e.g., they must include complete material history profiles). Based on this information, recommendations have been made for further work which is requir… more
Date: September 1, 1978
Creator: Rack, H.J. & Knorovsky, G.A.
Partner: UNT Libraries Government Documents Department
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Time-Dependent Liquid Metal Flows With Free Convection and Free Surfaces

Description: A finite element analysis is given for time-dependent liquid metal flows with free convection and free surfaces. Consideration is given to a two-dimensional shallow trough with vertical walls maintained at different temperatures. The spatial formulation incorporates mixed Lagrangian approximations to the velocity, pressure, temperature, and interface position. The time integration method is performed using the Trapezoid Rule with step-size control. The Galerkin method is employed to reduce the … more
Date: November 1, 1990
Creator: McClelland, M. A.
Partner: UNT Libraries Government Documents Department
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Computer simulation of solidification

Description: The current state-of-the-art of computer simulation of solidification was reviewed. Brief descriptions are given for methods of handling the latent heat of fusion and analog, finite element, finite difference, and pseudo-steady state technique used to simulate solidification. Methods of reducing manpower requirements are discussed as well as general purpose heat transfer codes currently available. Several examples of solidification simulation including die casting, welding, and die design appli… more
Date: January 1, 1978
Creator: Erickson, W.C.
Partner: UNT Libraries Government Documents Department
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Simulation of three-dimensional, time-dependent, incompressible flows by a finite element method

Description: A finite element model has been developed for simulating the dynamics of problems encountered in atmospheric pollution and safety assessment studies. The model is based on solving the set of three-dimensional, time-dependent, conservation equations governing incompressible flows. Spatial discretization is performed via a modified Galerkin finite element method, and time integration is carried out via the forward Euler method (pressure is computed implicitly, however). Several cost-effective tec… more
Date: January 1, 1981
Creator: Chan, S. T.; Gresho, P. M.; Lee, R. L. & Upson, C. D.
Partner: UNT Libraries Government Documents Department
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Impeller Flow-Meter Logging of Vertical Cross Flow Between Basalt Aquifers Through Wells at the Idaho National Engineering Laboratory, Eastern Snake River Plain, Idaho. Progress Report, June 22, 1992

Description: An impeller flowmeter was used with a COLOG digital acquisition system to determine existing borehole flows, to compare with previous logging results, and to acquire flow measurements of vertical cross-flow of water in the wells between permeable zones in the open-hole intervals. The direction of flow found was predominantly downward with velocities ranging from 0-30 ft/min. Some flow reversals were noted and attributed to nearby pumping wells. USGS wells 44 and 46 were studied in September, 19… more
Date: December 31, 1992
Creator: Bennecke, W. M. & Wood, S. H.
Partner: UNT Libraries Government Documents Department
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Most likely failure location during severe accident conditions

Description: This paper describes preliminary results from which finite element calculation results are used in conjunction with analytical calculation results to predict failure in different LWR vessel designs during a severe accident. Detailed analyses are being performed to investigate the relative likelihood of a BWR vessel and drain line penetration to fail during a wide range of severe accident conditions. Analytically developed failure maps, which were developed in terms of dimensionless groups, are … more
Date: December 31, 1991
Creator: Rempe, J. L. & Allison, C. M.
Partner: UNT Libraries Government Documents Department
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Structural aspects of superconducting fusion magnets

Description: Some methods for studying various static, dynamic, elastic-plastic, and fracture mechanics problems of superconducting magnets are described. Sample solutions are given for the UWMAK-I magnet. Finite element calculations were used. (MOW)
Date: January 1, 1977
Creator: Reich, M.; Lehner, J. & Powell, J.
Partner: UNT Libraries Government Documents Department
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