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Elastic and Plastic Strains and the Stress Corrosion Cracking of Austenitic Stainless Steels. Progress Report, April 30, 1977--December 30, 1977

Description: A newly developed test environment based on NaCl, Na/sub 2/SO/sub 4/, and HCl has provided some insight to several aspects of SCC in a transformable austenitic stainless steel. Current vs. time curves indicated the presence of the formation of a ''protective'' film which drastically reduced the anodic current leading to failure. This film, not indicated by the polarization curves, is subject to highly localized damage such as pitting. Thus, although it allows only very small corrosion currents,… more
Date: January 1, 1978
Creator: Troiano, A. R.
Partner: UNT Libraries Government Documents Department
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Fundamental Studies of Erosion for Coal Gasification Systems. Annual Progress Report, 1 November 1979-30 June 1980

Description: The effort in this program is divided between modelling the particle impact event using numerical methods and computer calculations and actual measurement of erosion rates. While the results obtained from each of these activities must be combined to provide an improved understanding of particulate erosion of ductile materials, it is convenient to describe separately the progress in each activity area. The first step in the application of the finite element method to any problem is the dissoluti… more
Date: July 27, 1980
Creator: Follansbee, P. S.; Sinclair, G. B. & Williams, J. C.
Partner: UNT Libraries Government Documents Department
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Dynamic shear behavior of alumina-filled epoxy

Description: Thin-walled tubular specimens of alumina-filled epoxy were loaded in torsion at a strain rate of approximately 10/sup 3/ s/sup -1/ using a stored-torque Kolsky bar. In addition to measuring the time resolved shear stress and shear strain in the specimen, the axial stress generated by the dilation of the material during shear deformation was also obtained as a function of time. Tests were conducted at room temperature and at -60/sup 0/C. At room temperature, a moderate amount of plastic deformat… more
Date: March 1, 1982
Creator: Costin, L.S.
Partner: UNT Libraries Government Documents Department
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Load relaxation studies of zircaloy-4

Description: The results of the present work have shown (1) the load relaxation data of Zircaloy-4 in the temperature range of 200/sup 0/C to 385/sup 0/C can be represented by the phenomenological model based on Hart's plastic equation of state; (2) the room temperature load relaxation data reflect the effects of deformation twinning; (3) at higher temperatures the load relaxation data suggest the contribution of grain boundary sliding; and (4) the effects of strain aging can be identified based on the load… more
Date: January 1, 1976
Creator: Huang, F. H.; Sabol, G. P.; McDonald, S. G. & Li, C. Y.
Partner: UNT Libraries Government Documents Department
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Physical processes of compaction companion report 1 to simulation of geothermal subsidence

Description: There are a variety of theories, techniques, and parameters in the subsidence literature. Biot's theory, Terzaghi's theory, and the theory of interacting continua (TINC) are used to explain solid-fluid interaction; stress-strain theories range from linear elastic to e-log p to plasticity and pore-collapse theories. Parameters are numerous: void ratio,, permeability, compaction coefficient, pore compressibility, Young's modulus, bulk modulus, shear modulus, Poisson's ratio, Lame coefficients, co… more
Date: March 1, 1980
Creator: Miller, I.; Dershowitz, W.; Jones, K.; Myer, L.; Roman, K. & Schauer, M.
Partner: UNT Libraries Government Documents Department
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Coal plasticity at high heating rates and temperatures. Y

Description: This report presents the Ph.D. Thesis Proposal of Mr. Sarakorn Gerjarusak to the MIT Department of Chemical Engineering on the topic: Plasticity Kinetics of Different Coal Types.'' A theoretical approach to the study of coal plasticity is described. Previous work relating the viscosity of molten coal to the inventory of metaplast employed a single chemical reaction model. In order to be able to use the kinetics parameters such as the activation energy obtained at one temperature-time history to… more
Date: August 1, 1991
Creator: Gerjarusak, S.; Peters, W.A. & Howard, J.B.
Partner: UNT Libraries Government Documents Department
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Acoustic emission from beryllium

Description: The acoustic emission from both powder and ingot source beryllium has been measured as a function of strain and prior heat treatment. Most measurements were made during tensile deformation, but a limited number of compression tests have also been performed. The acoustic emission observed was of the burst type, with little or no contribution from continuous type emission. The emission was characterized by the variation of burst rate and average energy per burst as a function of strain. The tensi… more
Date: June 9, 1976
Creator: Heiple, C. R. & Adams, R. O.
Partner: UNT Libraries Government Documents Department
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Load relaxation studies of a metallic glass

Description: Experimental results of load relaxation studies of a commercial metallic glass as a function of temperature are reported. The data suggest that metallic glasses exhibit deformation behavior with flow laws similar to those governing plastic deformation in crystalline solids. The lack of appreciable work hardening in annealed material and the identification of an anelastic component are also indicated by the experimental observations. (GHT)
Date: January 1, 1977
Creator: Hadnagy, T. D.; Krenisky, D. J.; Ast, D. G. & Li, C. Y.
Partner: UNT Libraries Government Documents Department
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Consistent stress-strain ductile fracture model as applied to two grades of beryllium

Description: Published yield and ultimate biaxial stress and strain data for two grades of beryllium are correlated with a more complete method of characterizing macroscopic strain at fracture initiation in ductile materials. Results are compared with those obtained from an exponential, mean stress dependent, model. Simple statistical methods are employed to illustrate the degree of correlation for each method with the experimental data.
Date: January 1, 1980
Creator: Priddy, T. G.; Benzley, S. E. & Ford, L. M.
Partner: UNT Libraries Government Documents Department
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Relationships Between Fracture Toughness and Other Material Properties. Final Report

Description: The key experimental and analytical studies which have led to our present understanding of the mechanisms of ductile fracture are reviewed. It is concluded that insufficient progress has been made in the quantitative description of ductile separation mechanisms on a microscale to allow the realistic prediction of fracture toughness from material properties and microstructure. An experimental study of ductile fracture is underway which has the aim of determining the growth rate of voids in known… more
Date: January 1, 1974
Creator: Perra, M. & Finnie, I.
Partner: UNT Libraries Government Documents Department
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Coal plasticity at high heating rates and temperatures

Description: The potential influence of gas bubbles on the viscosity of molten coal at elevated temperatures was estimated by calculations, using literature models for the viscosity of two and three phase suspensions. In one approach, gas bubbles in molten coal were approximated as the dispersed phase of deformable liquid globules in G.I. Taylor's model of emulsion viscosity. This model was incorporated into different models for the viscosity of solid-in-liquid suspensions, in which the dispersed solids are… more
Date: May 1, 1992
Creator: Gerjarusak, S.; Peters, W.A. & Howard, J.B.
Partner: UNT Libraries Government Documents Department
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Cladding failure by local plastic instability

Description: Cladding failure is one of the major considerations in analysis of fuel-pin behavior during hypothetical accident transients since time, location, and nature of failure govern the early postfailure material motion and reactivity feedback. Out-of-pile thermal transient tests of both irradiated and unirradiated fast-reactor cladding show that local plastic instability, or bulging, often precedes rupture and that the extent of local instability limits the initial rip length. To investigate the det… more
Date: December 1, 1977
Creator: Kramer, J. M. & Deitrich, L. W.
Partner: UNT Libraries Government Documents Department
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Deformation of superplastic alloys at relatively low strain rates

Description: The superplastic and sub-superplastic creep properties of Pb-Sn eutectic and Al-Zn eutectoid alloys were studied. Various thermomechanical treatments we tested to check the possibilities of whether the subsuperplastic deformation mechanism is affected by these treatments. All thermomechanical histories were found to reveal the same stress exponent, which is believed to be indicative of the predominant mechanism. The mechanical data in the low stress region lead us to suggest that dislocation gl… more
Date: February 1, 1978
Creator: Grivas, D.
Partner: UNT Libraries Government Documents Department
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Stress-point algorithm for a pressure-sensitive multiple-yield-surface plasticity theory

Description: A pressure-sensitive multiple-yield-surface plasticity theory is presented for application to the multi-dimensional cyclic response of soil media. A stress-point numerical algorithm is developed as the basis of a computer module designed to interface with large-scale finite element computer programs used at LLNL.
Date: March 1, 1982
Creator: Hughes, T.J.R.
Partner: UNT Libraries Government Documents Department
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User's manual for finite-element computer code, CREEP-PLAST

Description: CREEP-PLAST is a finite element computer code developed for high temperature structural design of LMFBR vessels, components and core structures. It performs creep and plasticity calculation in two dimensional form under plane stress, plane strain or axisymmetric assumptions. The original code has been extensively modified to improve its efficiency.
Date: January 1, 1978
Creator: Yang, C.I. & Zawadzki, S.
Partner: UNT Libraries Government Documents Department
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Inelastic bending of beams under time-varing moments: a state variable approach

Description: The inelastic response of a beam to several time-varying moments is presented. The constitutive equations used to describe the beam material are due to Hart. This is one of several state variable theories of inelastic deformation that have been proposed recently. Hart's equations have been previously shown to accurately predict the response of uniaxial specimens to time-varying loads. It is seen that Hart's theory is able to qualitatively simulate various phenomena in creep and plasticity such … more
Date: January 1, 1978
Creator: Chang, K.J.; Lance, R.H. & Mukherjee, S.
Partner: UNT Libraries Government Documents Department
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Effect of alloy deformation on the average spacing parameters of non-deforming particles

Description: It is shown on the basis of stereological definitions and a few simple experiments that the commonly used average dispersion parameters, area fraction (A/sub A/)/sub ..beta../, areal particle density N/sub A..beta../ and mean free path lambda/sub ..cap alpha../, remain invariant during plastic deformation in the case of non-deforming equiaxed particles. Directional effects on the spacing parameters N/sub A..beta../ and lambda/sub ..cap alpha../ arise during uniaxial deformation by rotation and … more
Date: February 1, 1980
Creator: Fisher, J. & Gurland, J.
Partner: UNT Libraries Government Documents Department
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Stress relaxation and hillock growth in thin films

Description: The relaxation of thermal stress in a thin film adhering to a substrate of differing expansion coefficient is discussed. Good agreement is found between literature data on relaxation during isothermal anneals of Pb films at up to 350/sup 0/K and model calculations based on a state variable description of plastic flow. The stress system during relaxation is explored, and the absence of diffusional creep is explained. The plasticity-dominated relaxation process suggested by this analysis is shown… more
Date: January 1, 1978
Creator: Jackson, M. S. & Li, C. Y.
Partner: UNT Libraries Government Documents Department
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A Unified and Mechanistic Approach to Creep-Fatigue Damage

Description: A new creep-fatigue equation is proposed that takes into account both plastic strain and strain rate. The coefficients and exponents in the damage-rate equation are interpreted by means of the various damage mechanisms of the material. The damage-rate equation has been integrated to analyze various phenomena such as the effects of plastic strain rate on monotonic tensile or creep rupture time, rising mean strain on the low-cycle fatigue behavior at elevated temperature, tensile and compressive … more
Date: January 1976
Creator: Majumdar, S. & Maiya, P. S.
Partner: UNT Libraries Government Documents Department
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PTA-1: A Computer Program for Analysis of Pressure Transients in Hydraulic Networks, Including the Effect of Pipe Plasticity

Description: The computer program PTA-1 performs pressure-transient analysis of large piping networks using the one-dimensional method of characteristics applied to a fluid-hammer formulation. The effect of elastic-plastic deformation of piping on pulse propagation is included in the computation. The program is particularly oriented toward the analysis of the effects of a sodium/water reaction on the intermediate heat-transport system of a liquid-metal-cooled fast breeder reactor, but may be applied just as… more
Date: November 1976
Creator: Youngdahl, C. K. & Kot, C. A.
Partner: UNT Libraries Government Documents Department
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Numerical Integration of Large Deflection Elastic-Plastic Axisymmetric Shells of Revolution

Description: The improvement in the method of large deflection elastic-plastic analysis of shells and other structures appears to have continued interest. With the development in this work an improved numerical suppression scheme is now available for the large deflection elastic-plastic analysis of axisymmetric shells of revolution subjected to symmetric loadings. Quasi-linearization of Sander's non-linear shell equations is presented for the first time. With these quasi-linearized equations the suppression… more
Date: December 1976
Creator: Ahmed, Habib Uddin
Partner: UNT Libraries Government Documents Department
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Elastic-Plastic Constitutive Modeling of Concrete

Description: The need to understand concrete behavior under high temperatures in the nuclear industry has become rather acute. For this purpose, a constitutive model of concrete especially developed for this severe environment is indispensable. This report reviews the presently available constitutive models of concrete at standard-temperature conditions and considers their advantages and drawbacks. A rather simple but effective approach is selected to treat concrete behavior at high temperatures. Special em… more
Date: March 1983
Creator: Takahashi, Yukio
Partner: UNT Libraries Government Documents Department
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Accurate Numerical Solutions for Elastic-Plastic Models

Description: The accuracy of two integration algorithms is studied for the common engineering condition of a von Mises, isotropic hardening model under plane stress. Errors in stress predictions for given total strain increments are expressed with contour plots of two parameters: an angle in the pi plane and the difference between the exact and computed yield-surface radii.
Date: March 1980
Creator: Schreyer, H. L.; Kulak, R. F. & Kramer, J. M.
Partner: UNT Libraries Government Documents Department
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Geomechanics of bedded salt

Description: Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temper… more
Date: June 8, 1979
Creator: Serata, S. & Milnor, S. W.
Partner: UNT Libraries Government Documents Department
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