Showing papers on "Material properties published in 1970"
TL;DR: In this article, the response of a finite-width composite laminate under uniform axial strain is treated through the application of classical elasticity theory, and finite-difference solution techniques are employed to obtain solutions for stresses and displacements throughout the region.
Abstract: The response of a finite-width composite laminate under uniform axial strain is treated through the application of classical elasticity theory. Finite-difference solution techniques are employed to obtain solutions for stresses and displacements throughout the region. Results for material properties typical of a high modulus graphite-epoxy composite material system are presented which explain the mechanism of shear transfer within a symmetric laminate. In addition, results of this work are compared to those given in a recent approximate formulation.
1,048 citations
TL;DR: In this paper, deviations from ideality in the form of thermodynamic excess functions, (X-Xo), have been computed for the volume, Gibbs energy, entropy, enthalpy, and energy for HF(g) between 292.69 and 329.15 K up to and including the saturation pressure.
56 citations
TL;DR: In this article, the effects of increasing the number of particles and making the calculations according to quantum mechanics instead of classical mechanics are both studied and compared with approximate lattice dynamics and cell-model predictions.
50 citations
TL;DR: In this paper, a variational approach is applied in predicting the thermodynamic properties of the liquid mixture of argon and krypton at zero pressure and 115.77°K.
Abstract: The variational technique proposed earlier for the calculation of the equilibrium thermodynamic properties of simple pure fluids, melting transitions, and simple pure solids is extended to binary mixtures of simple fluids. The working inequality is introduced and the variational parameters are characterized. For a case study, the present variational approach is applied in predicting the thermodynamic properties of the liquid mixture of argon and krypton at zero pressure and 115.77°K. The thermodynamic and excess properties of this mixture over that of the pure systems (at zero pressure and in liquid state) are calculated and compared with the results of the available Monte Carlo calculations, experimental measurements, and several theories of solutions. Preliminary investigation indicates good agreement between the result of the present variational technique with the experimental and machine‐calculated data. Variations of the thermodynamic properties of the binary mixture, with the variation of the ratios of the force constants of the potential functions of the two components, are calculated at 97°K, zero pressure, and equal mole fractions. These values are compared with the existing values of the Monte Carlo calculations.
49 citations
44 citations
01 Feb 1970-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: The ratio of vapor pressures of gold in equilibrium with liquid gold and with each of eleven Au−Pt alloys has been measured over the approximate temperature range of 1340° to 1520°K by means of a dual-chamber effusion cell and a mass-spectrometric detection system as mentioned in this paper.
Abstract: The ratios of vapor pressures of gold in equilibrium with liquid gold and with each of eleven Au−Pt alloys have been measured over the approximate temperature range of 1340° to 1520°K by means of a dual-chamber effusion cell and a mass-spectrometric detection system. From these ratios, thermodynamic activities and related integral and partial molar thermodynamic quantities have been evaluated at 1423°K. When the thermodynamic quantities are referred to a hypothetical standard state of superheated gold at 1423°K, the results indicate both substantial positive deviations from ideal behavior and positive molar heats of mixing as is expected for miscibility-gap systems. The integral moalr quantities are adequately predicted by either the subregular or the Lumsden model. Observed integral entropies are discussed in terms of thermal, electronic, and configurational contributions, whereas the positive integral molar free energies are tentatively attributed to strain effects arising from ion-core repulsions.
19 citations
DOI•
01 Nov 1970TL;DR: In this article, phase equilibria and thermodynamic properties of the system CaO−FeO+Fe2O3−SiO2 were studied at 1450° and 1550°C, over a range of pO2 from 1 to about 10−11 atm.
Abstract: Phase equilibria and thermodynamic properties of the system CaO−FeO−Fe2O3−SiO2 were studied at 1450° and 1550°C, over a range ofpO2 from 1 to about 10−11 atm. Isothermal phase diagrams and activity-composition diagrams were constructed for 0, 5, 10, 20, and 30 wt pct SiO2 sections. The data are applicable to further understanding the behavior of simple BOF steelmaking slags.
19 citations
18 citations
TL;DR: The definition of the thermodynamic pressure of a quantum mechanical system of hard core particles is considered for a wide variety of boundary conditions and a large class of interactions in this paper, and it is shown that the pressure can be defined for elastic walls and that in the limit of an infinite system the pressure both exists and is independent of the coefficient of elasticity.
Abstract: The definition of the thermodynamic pressure of a quantum mechanical system of hard core particles is considered for a wide variety of boundary conditions and a large class of interactions. It is shown that the pressure can be defined for elastic walls and that in the limit of an infinite system the thermodynamic pressure both exists and is independent of the coefficient of elasticity. Similarly if repulsive wall boundary conditions are used the thermodynamic pressure exists. Unfortunately it has not been possible to demonstrate that the two pressures obtained are identical but a number of their properties and interrelationships are established.
14 citations
TL;DR: In this article, Fichter et al. extended Hedgepeth's work to include multiple slits and developed a solution pattern for holes of arbitrary cross-section following the solution pattern established by hedgepeth in 1961.
TL;DR: In this article, the free energies, enthalpies and entropies of the solution process of CaSO4 were derived from know solubility data between 0 and 200 °C.
Abstract: The thermodynamic solubility products of CaSO4 and the free energies, enthalpies and entropies of the solution process have been obtained from know solubility data between 0 and 200 °C by calculating the activity coefficients of CaSO4 at high temperatures by means of the Bjerrum treatment of ion association. The thermodynamic solubility product of the n-hydrate is then given by K°sp=m2sγ2±anw and the thermodynamic functions are derived from this and tabulated.
TL;DR: In this article, a set of general governing equations is derived for the study of free vibrations of rectangular plates composed of a transversely isotropic material, including the effects of transverse shear deformation and rotatory inertia.
Abstract: A set of general governing equations is derived for the study of free vibrations of rectangular plates composed of a transversely isotropic material, including the effects of transverse shear deformation and rotatory inertia. Such a formulation is necessary for even geometrically thin plates, when the ratio of in-plane modulus of elasticity to transverse shear modulus is large (i.e., 20-50) which occurs in vapor deposited materials such as pyrolytic graphite, and in many fiber reinforced composite materials. The corresponding equations for beams are also derived. The case of a simply supported plate is treated in detail. Numerical results show that significant differences occur in predicting natural frequencies for various modes when the present theory is used compared to the use of classical methods for plates of these material systems. Classical methods can predict frequencies that are erroneous by a factor of nearly three.
TL;DR: In this paper, the applicability of the technical theory over a range of material properties and geometries was evaluated for the specific case of a three-layer beam, and the dependence of the geometrical and mechanical properties of the individual layers on the stresses and displacements was shown.
Abstract: Equations for stresses in a laminated orthotropic curved beam based on the technical theory assumption (Winkler) are presented. The formulation of the same problem by orthotropic elasticity is indicated. In order to assess the applicability of the technical theory over a range of material properties and geometries, the specific case of a three-layer beam was studied. Results of the technical theory were compared with those using elasticity. The dependence of the geometrical and mechanical properties of the individual layers on the stresses and displacements is shown. Some interesting results are shown with the aid of numerical examples.
TL;DR: In this paper, a numerical method is presented for the stress analysis of reactor graphitic components under conditions of plane stress, plane strain, generalized plane strain or axisymmetry, both the creep deformation and the irradiation-induced strains are the major concern.
Journal Article•
TL;DR: In this paper, the authors developed a methodology to evaluate LAYERED systems with non-uniformor MATERIAL PROPERTIES, and the results show that the response of the Llayered system is inFLUENCED by the statistical LCHARACTERISTICS of the Materials.
Abstract: A PROCEDURE WAS DEVELOPED TO EVALUATE LAYERED SYSTEMS WITH NONUNIFORM MATERIAL PROPERTIES. THE PROCEDURE CONSISTS OF DEFINING THE LAYERED SYSTEM BY A PHYSICAL MODEL CONSISTING OF MASS POINTS TIED TOGETHER BY SPRINGS AND BARS. THE VARIABILITY OF THE MATERIAL IS SIMULATED BY ASSIGNING DIFFERENT CHARACTERISTICS OF THE MTERIAL PROPERTIES TO SPRINGS CONNECTING THE MASS POINTS. ASSIGNMENT OF VALUES REPRESENTING THE MATERIAL PROPERTIES IS DONE ON A RANDOM BASIS. THE RANDOM VALUES ARE GENERATED IN A MANNER THAT PRODUCES A MODEL WITH MEAN CHARACTERISTICS CORRESPONDING TO THE MEAN PROPERTIES OF THE MATERIALS IN THE VARIOUS LAYERS OF THE PAVEMENT, AND WITH A COEFFICIENT OF VARIATION OF THE CORRESPONDING PAVING MATERIAL. RESULTS SHOW THAT THE RESPONSE OF THE LAYERED SYSTEM IS INFLUENCED BY THE STATISTICAL LCHARACTERISTICS OF THE MATERIALS. THE STATISTICAL NATURE OF THE RESPONSE IS INFLUENCED BY BOTH THE VARIABILITY OF THE MATERIAL AND THE NATURE OF THE VARIABILITY. A LARGE AREA WITH SLIGHTLY LESS THAN AVERAGE STIFFNESS HAS A GREATER INFLUENCE ON THE RESPONSE OF THE SYSTEM THAN A LARGE DIFFERENCE IN STIFFNESS OVER A SMALL AREA. THUS, DETAILED ANALYSES ARE NECESSARY TO OBTAIN A COMPREHENSIVE UNDERSTANDING OF THE BEHAVIOR OF THE SYSTEM. MUCH WORK STILL NEEDS TO BE DONE TO OBTAIN A COMPLETE PICTURE OF THE STATISTICAL NATURE OF PAVEMENT RESPONSE. PRELIMINARY RESULTS STRONGLY INDICATE A NEED FOR THE TYPE OF ANALYSIS PRESENTED IN THE PAPER AS A GUIDE FOR ESTABLISHING REALISTIC QUALITY CONTROL CRITERIA FOR PAVING MATERIALS. WITH RESULTS FROM SUCH A PROCEDURE IT IS POSSIBLE TO ESTABLISH A COST BENEFIT FROM HIGHER QUALITY CONTROL CRITERIA. /AUTHOR/
TL;DR: In this paper, the porosity and strength of porous materials are derived assuming a simple cubic porous structure, and the theoretical expressions are compared with experimental data on porous beryllium and stainless steel materials, and good agreement is shown.
Abstract: Design of systems utilizing porous materials, e.g., transpiration-cooled systems, may place requirements on both, mechanical and flow-control (permeability) properties. Equations relating porosity and strength are developed assuming a simple cubic porous structure. The theoretical expressions are then compared with experimental data on porous beryllium and stainless steel materials, and good agreement is shown. Implicit relations are then developed which relate permeability to strength and density, and which include a materialdependent constant that is determined experimentally. Empirical fits to these relations are then manipulated to show some practical design consequences. It is seen that for a given material with required permeability for design, there is an optimum particle size which will yield maximum strength. The maximum strength, which varies with permeability to the minus i power, is determined for the beryllium and stainless steel example materials. It is also seen that the relative density, for maximum strength, is 0.81 (porosity of 0.19) which is independent of the material and the permeability.
TL;DR: A theoretical elastoplastic material modeling of the functionally graded material is presented in this paper, where an analytical methodology is shown for studying a crack in a functional graded material subjected to an intense thermal shock load.
Abstract: An analytical methodology is shown for studying a crack in a functionally graded material subjected to an intense thermal shock load. A theoretical elastoplastic material modeling of the functionally graded material is presented. Also independently a computational procedure of an elastoplastic constitutive law is introduced with the use of a micromecnanics analysis and a hierarchical neural network algorithm. The material is composed of ZrO and 77-6A/-4V, where the plastic flow is considered to occur in the titanium alloy phase. To detect the crack-tip fracture severity in the highly inhomogeneous media, r*integral parameter is employed for the thermal shock problem of the cracked material. Introduction In high temperature technology, multi-material bodies comprised of ceramics and high toughness materials such as metals have been thought. The discrepancies in the thermal expansion rates and other material properties between the materials causes a strength problems at the interface. Functionally graded material(FGM) is, hence, devised in the manner that the material composition is continuously varied with location in order to remove the strain discontinuity. By properly grading the composition of the constituents, the thermal stresses in the FGM may be minimized. FGM is, thus, inherently inhomogeneous, and in addition thermally inhomogeneous such that the material properties change over the wide range of temperature to that the material is designated to be subjected. The FGM is still on the materials research and development stage. To design the material, the prompt establishment of the analytical methodology is urged. For the analysis of such a material behavior and the structure, rapidly developing computational mechanics is best suited for its complexity. In the computational analysis of the FGM, the local macroscopic constitutive law for the averaged medium, where the matrix and/or the inclusion phases undergo thermo-elastoplasticity, must be known. When plastic flow occurs, if the volume fraction of the inclusion phase is high, interactions between inclusions may give a significant Transactions on Engineering Sciences vol 13, © 1996 WIT Press, www.witpress.com, ISSN 1743-3533
01 Jul 1970
Abstract: Thermodynamic properties of dilute solutions of oxygen in the system Fe-Ni-Co have been studied by means of the hydrogen-water vapor equilibrium. Evidence is presented which shows Henry’s Law is obeyed by oxygen within experimental error over a substantial composition range. The standard Gibbs energy of solution of oxygen surface is presented for the entire system at 1550°C. Equations are presented which show the variation of the standard Gibbs energy of solution of oxygen as a function of temperature for five compositions of equal Ni-Co ratio.
DOI•
01 Jan 1970
TL;DR: In this paper, a model for the stress-strain relationship, the variation of the yield strength, and the residual stresses across the section have been established based on the experimental results, where the proposed material models have been incorporated within a large deformation elasto-plastic shell finite element.
Abstract: Experimental investigations to evaluate the mechanical properties, and the built in residual stresses of channel-shaped cold-roll-formed steel sections are reported in this paper. Tensile coupon tests were used to evaluate the mechanical properties at the flat zones and at the corner zones of the sections. Electrical resistance strain gauges with an "Electrical Discharge Machining" cutting technique was used to establish the magnitudes, and the distributions of residual stresses. Based on the experimental results, analysis models for the stress-strain relationship, the variation of the yield strength, and the residual stresses across the section have been established. The proposed material models have been incorporated within a large deformation elasto-plastic shell finite element to form a model for cold-formed steel sections. The efficiency and the accuracy of the proposed material properties models, as applied to a finite element model has been evaluated against corresponding experimental results of cold-formed steel sections subjected to axial compressive loads.
01 Jul 1970
TL;DR: In this article, the PREDIX materials research program is described with particular reference to obtaining experimental data on dynamic behavior of metals, intended for use in theoretical modeling of material behavior and development of computer codes for predicting material response.
Abstract: : The PREDIX materials research program is described with particular reference to obtaining experimental data on dynamic behavior of metals. These data are intended for use in theoretical modeling of material behavior and development of computer codes for predicting material response. A qualitative analysis is given of results obtain in the general areas of stress-strain-strain rate behavior, equation of state, compressive and release wave characteristics, fracture, and thermally degraded properties. Also, the use of experimental data in evaluating models and calculations is discussed. Details of the tests conducted on aluminum, titanium, copper and tantalum, as well as a review of experimental techniques, are given in subsequent volumes in this series. (Author)
DOI•
01 Jan 1970
TL;DR: In this article, a 3D model of a concrete block with single hole under diametrical hydraulic jack force is idealised as a finite element model with 2308 nodes and 582 solid elements and used as the prototype in this study.
Abstract: This paper describes how finite element analyses were used to develop a method of in-situ determination of concrete material properties. A 3-D model of a concrete block with single hole under diametrical hydraulic jack force is idealised as a finite element model with 2308 nodes and 582 solid elements and is used as the prototype in this study. The strains, stresses and deformations of the block for nine possible combinations of Young's modulus E and Poisson's ratio v were used to determine the variation of strain at radial gauge locations. The relationship between strain and material property for the block with fixed geometry is investigated numerically, from which a formula is derived for E and v in terms of the measured in-situ strains. The practical application of the technique on a real structure is also presented.
TL;DR: In this article, the influence of inelastic material properties on spherical wave propagation in granitic rock is studied in terms of shear and variable bulk moduli, a yield criterion and flow rule.
Abstract: This paper studies the influence of inelastic material properties on spherical wave propagation in a granitic rock. Constitutive equations are derived from experimental data in terms of shear and variable bulk moduli, a yield criterion and flow rule. The effect of varying the amount of volumetric hysteresis, the yield criterion and the flow rule are studied in a series of calculations. The rate at which stress attenuates is more strongly affected by volumetric properties, such as plastic dilatancy and hysteretic compaction under hydrostatic loading and unloading, than by other material properties. Also, the yield or fracture criterion on unloading is far more relevant to spherical wave propagation than is the criterion on loading.
TL;DR: In this article, the construction and operation of an instrument for measuring tensile stress relaxation and creep, particularly of polymers, is described, which is comparatively inexpensive to build and enables measurements to be carried out in vacuo or in a controlled atmosphere of gas or vapor.
Abstract: The construction and operation of an instrument for measuring tensile stress relaxation and creep, particularly of polymers, is described. The instrument is comparatively inexpensive to build and enables measurements to be carried out in vacuo or in a controlled atmosphere of gas or vapor. The design is based on principles used for some earlier stress relaxometers modified to enable characterization of samples having a very wide range of moduli either as stress relaxation or, additionally, as creep measurements. The instrument can therefore be used to evaluate material properties of hard plastics or of soft rubbers when exposed to selected environments.
TL;DR: In the field of high pressure research, several kinds of apparatus have been developed which are capable of maintaining simultaneously pressures up to ∼ 100 kilobars and temperatures above 2000°C (2275K) as mentioned in this paper.
Abstract: Within the past few years several kinds of apparatus have been developed which are capable of maintaining simultaneously pressures up to ∼ 100 kilobars and temperatures above 2000°C (2275K). This development has expanded tremendously the field of investigation of chemical reactions, phase changes, and physical properties of materials under extreme conditions. At the present time interest and activity in the field of high-pressure research are increasing rapidly.