Showing papers on "Elastic modulus published in 1970"
TL;DR: In this article, a generalized equation for the relative elastic moduli of composite materials is proposed by the introduction of a generalized Einstein coefficient and a function which considers the maximum volumetric peak fraction of the filler phase.
Abstract: A generalized equation is proposed for the relative elastic moduli of composite materials. By the introduction of a generalized Einstein coefficient and a function which considers the maximum volumetric peaking fraction of the filler phase, the moduli of many types of composite systems can be calculated.
484 citations
TL;DR: Analysis of the data indicates that the elastic modulus increases concavely upward with strain and varies between 1·0 × 103 and 3·5 × 103 dyn/cm2 for the range of strain tested.
158 citations
TL;DR: Comparison between the moduli in the two directions revealed that the arterial wall is not isotropic at physiological pressures because the circumferential elastic modulus is greater than the longitudinal modulus.
Abstract: Segments of dog carotid artery were held at in-situ length and studied in vitro after excitation of the muscle with norepinephrine and after poisoning of the muscle with potassium cyanide. In-situ length corresponded to a longitudinal strain of .57±.02 relative to the unstretched length. The longitudinal elastic modulus was about 4.1x106 dyn/cm2 at in-situ length and zero transmural pressure. This value was not altered by excitation of the vascular smooth muscle. The longitudinal stress due to traction decreased as the longitudinal stress due to transmural pressure increased, and it was suggested that this interaction underlies the relative constancy of vessel length in situ. The Poisson's ratio between the circumferential and longitudinal directions was about 0.3 and was found to decrease slightly with activation of the vascular muscle. The data for the longitudinal modulus and for Poisson's ratio were used to compute the circumferential elastic modulus. Activation of the muscle increased the circumferen...
112 citations
TL;DR: In this article, it was shown that the magnitude of elastic shear modulus in b.c. transition metals is derived almost completely from the number of electrons per atom in the unfilled d electron bands.
110 citations
01 May 1970-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this paper, the effects of volume fraction of the WC phase, the carbon content, and the WC particle-size on the elastic moduli were investigated in some detail, and it was concluded that elastic behavior of the alloys can be essentially predicted on the basis of a simplified geometrical model of WC particles embedded in continuous cobalt matrix.
Abstract: Measurements of Young’s modulus, shear modulus, compression modulus, and Poisson’s ratio on WC-(1 ~ 30) wt pct Co alloys were carried out by dynamic resonance method. The effects of volume fraction of the WC phase, the carbon content, and the WC particle-size on the elastic moduli were investigated in some detail. The result shows that the various elastic moduli of the alloys depend solely on volume fractions of the constituent phases and they invariably fall within Hashin and Shtrikman’s bounds. Moreover, the moduli are found to be approximated by Paul’s “strength of materials” type formulas. It is concluded that elastic behavior of the alloys can be essentially predicted on the basis of a simplified geometrical model of WC particles embedded in continuous cobalt matrix.
107 citations
TL;DR: In this paper, the elasticity modulus of a fluidized bed has been calculated from a drag force-interparticle distance relation, and a satisfactory criterion for the transition between homogeneous and heterogeneous fluidization has been obtained.
100 citations
78 citations
TL;DR: The velocity of sound has been measured in argon single crystals by the pulse-echo technique for both longitudinal and transverse waves from 3 to 77 degrees K as mentioned in this paper, and the values of the elastic constants obtained by extrapolation of the results to 0 degrees K are: c11=4.39, c12= 1.83 and C44=1.64, in units of 109N m-2.
Abstract: The velocity of sound has been measured in argon single crystals by the pulse-echo technique for both longitudinal and transverse waves from 3 to 77 degrees K. The values of the elastic constants obtained by extrapolation of the results to 0 degrees K are: c11=4.39, c12= 1.83 and C44=1.64, in units of 109N m-2. Comparison with several lattice dynamical models indicates that models incorporating only central two-body forces are inadequate. New values for the adiabatic bulk modulus permit more accurate calculation of the Debye characteristic temperature and the Gruneisen parameter.
72 citations
TL;DR: In this paper, the Halpin-Tsai equations are used to estimate the longitudinal shear modulus of fiber reinforced composites, and a simple but approximately precise formula to interpolate the existing exact machine calculations available in the current literature is presented.
Abstract: It has been suggested [1] that it is often advantageous for design purposes to be able to rapidly calculate accurate estimates for the elastic moduli of fibre reinforced composites, and that a simple but approximately precise formula to interpolate the existing exact machine calculations available in the current literature is to be desired. The Halpin-Tsai equations, presented in [1], aim to satisfy this need, and the expression for estimating the longitudinal shear modulus is given as:
69 citations
TL;DR: Elastic properties for reinforced composite material with hollow spherical inclusions embedded in the matrix were determined for the case of reinforced composite materials as mentioned in this paper, where the inclusions were embedded in a hollow spherical sphere.
Abstract: Elastic properties determined for reinforced composite material with hollow spherical inclusions embedded in matrix
64 citations
TL;DR: If the circumferential elastic modulus is assumed to vary in a parabolic manner through the wall thickness, maximum stresses occur within the endocardial layers, a result in qualitative agreement with experimental studies.
TL;DR: In this paper, the elastic moduli of the material determined from these wave-propagation measurements are compared with previously reported single-crystal and polycrystalline aluminum data at elevated temperatures.
Abstract: Elastic waves were generated in slender polycrystalline 2024 aluminum rods by the deposition of laser energy into the ends of the rods with a Q-switched laser. The propagation velocities of the waves were measured in the temperature range of 22° to 500°C. The elastic moduli of the material determined from these wave-propagation measurements are compared with previously reported single-crystal and polycrystalline aluminum data at elevated temperatures. Elastic moduli for polycrystalline 2024 aluminum agree with other reported data below about 200°C. Above this temperature, the 2024 aluminum moduli were found to decrease more rapidly with temperature than did those for single-crystal aluminum, although not as drastically as has been previously reported for polycrystalline aluminum.
TL;DR: The elastic moduli derived from sound velocity measurements show a step at the 105°K-transformation as discussed by the authors, which is a consequence of the coupling between the rotational motion of the oxygen octahedra and the elastic strain.
TL;DR: In this paper, the fracture toughness of glass bead, short glass fiber and randomly oriented short graphite fiber polyphenylene oxide composites was investigated. But the results were limited to the case when no polymer-filler adhesion was present.
Abstract: The mechanical properties of glass bead, randomly oriented short glass fiber and randomly oriented short graphite fiber polyphenylene oxide composites were investigated. Fracture toughness measurements were made using double edge-notched tensile specimens and tensile strength, tensile strain and initial elastic modulus were measured in standard ASTM tensile tests. It was found that the fracture toughness was relatively independent of filler types and geometry (and nearly equal to that of the unfilled polymer) when no polymer-filler adhesion was present. When adhesion was promoted by surface treatment of the reinforcement, the fracture toughness of the treated fiber composites was greater than that of the untreated composites, while that of the treated particulate composites was below that of the untreated materials. The fracture toughness was also relatively independent of fiber concentration, but decreased sharply with increased glass bead concentration. The elastic moduli of the composites vari...
TL;DR: In this article, the resonant frequencies of thin prismatic bars can be measured in vacuum over a wide temperature range, and it is concluded that the temperatures at which the Young's modulus-temperature curves begin to deviate from linearity correspond to the lowest temperatures in which plastic deformation can take place.
TL;DR: The adiabatic elastic moduli of singlecrystal Zr vary linearly with hydrostatic pressures up to 4.7 kbar as discussed by the authors, and the average high-temperature Gruneisen mode γH calculated from this data is in wide disagreement with that calculated from the volume thermal expansion coefficient.
Abstract: The adiabatic elastic moduli of single‐crystal Zr vary linearly with hydrostatic pressures up to 4.7 kbar. The pressure derivatives are dC11/dP=3.93, dC33/dP=5.49, dC44/dP=−0.22, dC66/dP=0.26, dC12/dP=3.42, and dC13/dP=4.25. The average high‐temperature Gruneisen mode γH calculated from this data is in wide disagreement with that calculated from the volume thermal expansion coefficient. It is proposed that this disagreement arises because the negative dC44/dP is caused by the change with pressure in the c/a ratio, rather than the volume change.
TL;DR: The effect of auxin on elastic extensibility has been investigated by means of the resonance frequency melhod in Pisum, sativum and the assumption has been made that a decrease in elastic modulus indicates a change in the cell wall which in some way is conducive to growth (induction of elongation).
Abstract: The effect of auxin on elastic extensibility has been investigated by means of the resonance frequency melhod in Pisum, sativum. The time lag for the decrease in Young's modulus E, caused by IAA, was between 2 and 3 minutes in etiolated stem internodes. The time lag for growth was about 7 minutes. The measurements of E in root segments were only qualitative owing to the structural characteristics; IAA decreases E in roots as it does in stems, but only in the region where IAA is assumed to enhance elongation. The connexion between elastic modulus and growth is discussed with reference to other investigations. The assumption has been made that a decrease in elastic modulus indicates a change in the cell wall which in some way is conducive to growth (induction of elongation). The theoretical possibilities of changing E have been discussed with reference to the formula for water fluxes. Both a change in a cell wall properly and a change in the cytoplasmic permeability are able to cause a change in E in the same way as auxin does. An early action of auxin must be located in the cell-wall-plasmalemma region.
TL;DR: In this article, an application of the displacement finite element method to axisymmetric soil-structure interaction problems is described, where the structure and foundation are analyzed as an entity, and the distribution of contact pressure does not have to be assumed.
Abstract: An application of the displacement finite element method to axisymmetric soil–structure interaction problems is described. Since the structure and foundation are analyzed as an entity, the distribution of contact pressure does not have to be assumed. The accuracy of the method is first assessed in the analysis of some simple problems to which other solutions exist. Then a series of laboratory results and one field case record, all involving flexible structures bearing on cohesionless foundations are analyzed, the foundations being treated as elastic but inhomogeneous. Both "Winkler" and elastic solid foundations are considered and it is shown that for the latter type physically reasonable distributions of the elastic modulus do not lead to very good predictions of the deflections of the structure although the deflections within the foundation itself are in agreement with observed values.
TL;DR: In this paper, the authors investigated the effect of the clear distance between inclusions on the stress distribution in a two-phase material and found that for a single inclusion in an extended matrix, the stress concentration in the matrix slightly depends on the matrix elastic modulus.
TL;DR: The sonic velocity curve of hair for its initial 20%–25% extension can be reproduced in isolated α-kerat in filaments, and is not observed in other keratins.
TL;DR: In this article, a model of a deformed lattice structure with point defects produced by irradiation is proposed, and it is shown that the anisotropy of a polymer crystal (difference between the elastic modulus along the molecular axis and perpendicular to the axis) increases the range of distortion in a crystal caused by a defect.
Abstract: The melting temperature of polyethylene crystals decreases and the lattice constants (both a and b) and lattice distortion increase, but the macroscopic volume of the specimen does not change with electron irradiation. From these results a model of a deformed lattice structure with point defects produced by irradiation is proposed. Calculations indicate that the anisotropy of a polymer crystal (difference between the elastic modulus along the molecular axis and perpendicular to the axis) increases the range of the distortion in a crystal caused by a defect. The presence of lattice distortion in electron irradiated polymer single crystals produces observable features in the Moire patterns obtained from the crystals.
TL;DR: In this paper, the elastic moduli of isolated polymer chains and of polymer-chains in crystals were derived for trigonal and orthorhombic crystals using B submatrices as used in normal coordinate treatments.
Abstract: A new general method was derived for calculating elastic moduli of isolated polymer-chains and of polymer-chains in crystals. Equations for elastic moduli were written with the B submatrices as used in normal coordinate treatments. The new method was applied for calculating the elastic moduli of (poly)oxymethylene chains in trigonal and orthorhombic crystals.
TL;DR: In this paper, the influence of mix parameters on the strength and deformation of plain concrete subjected to uniaxial tensile or compressive stress was examined and the results obtained from 94 mixes were used to develop charts which permit reasonably accurate prediction of any of the four properties listed above for a wide range of mixes.
Abstract: Synopsis The paper examines the influence of mix parameters upon the strength and deformation of plain concrete subjected to uniaxial tensile or compressive stress. Parameters considered are the effective water/cement ratio, aggregate/cement ratio, aggregate maximum size and grading defined in terms of mean particle size, and the strength, elastic modulus and crushing value (B.S. 812) of the coarse aggregate. Tensile and compressive strength, tensile strain at failure and compressive strain at 50 % compressive strength are related to each parameter in turn, often by expressing the values in relative terms. The results obtained from 94 mixes are used to develop charts which permit reasonably accurate prediction of any of the four properties listed above for a wide range of mixes.
01 Jan 1970
Journal Article•
01 Jan 1970-Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy
TL;DR: No significant difference in mechanical properties were found between normal-appearing hair and hair from patients with male pattern baldness, alopecia areata and various types of female defluvium capillorum.
TL;DR: In this paper, the authors used the transformed section concept of Mechanics of Materials (MOM) and derived expressions to employ flexural test results on cylindrical specimens (i.e., drill cores) in determining the tensile Modulus of Elasticity.
01 Jan 1970
TL;DR: In this article, a sonic resonance technique was used to investigate the room-temperature elastic and anelastic properties of physically mixed U0.8PU0.2O2 as a function of density, stoichiometry, and cation homogeneity.
Abstract: A sonic resonance technique was used to investigate the room-temperature elastic and anelastic properties of physically mixed U0.8PU0.2O2 as a function of density, stoichiometry, and cation homogeneity. The effect of porosity on the elastic moduli was linear and is described by E=2102.7 (1–2.03P)± 13.5 Kbars for the Young's modulus, G=823.5(1–2.05P)± 9.1 kbars for the shear modulus, and B= 1584.8(1–1.89P)± 59.1 kbars for the bulk modulus, where P is the volume fraction porosity. Poisson's ratio was 0.28 and was not a function of porosity. The Debye temperature of U0.8Pu0.2O2 computed from the Young's and shear moduli for theoretically dense specimens was 379°K. Variation of the O/M ratio from 1.968 to 2.006 produced no significant change in either the damping capacity or the elastic moduli of single-phase 80%UO2-20% PuO2 solid solutions. An approximate 24% decrease of the room-temperature Young's and shear moduli and an approximate increase by a factor of 14 in the internal friction were observed with gross modifications of plutonium cation homogeneity. Preliminary results suggest that internal friction measurements might be used to assay the homogeneity of UO2-PuO2 solid solutions.