Showing papers on "Young's modulus published in 1979"
TL;DR: In this article, the transverse mechanical resonant frequencies of cantilever beams have been used to calculate Young's modulus of the insulating thin films, which is applicable to a wide range of materials and deposition procedures.
Abstract: Electrostatically deflectable cantilever beams (1000–9000 A thick, 120–8.3 μm long) have been fabricated from a number of thin insulating films prepared by a variety of deposition methods. Measurements of the transverse mechanical resonant frequencies of these beams have been used to calculate Young’s modulus of the insulating thin films. This new technique is relatively simple and accurate and is applicable to a wide range of materials and deposition procedures.
313 citations
TL;DR: In this article, the variations in the compressive strength, splitting and flexural-tension strengths, and the modulus of elasticity of concrete are reviewed, and representative probability distributions are suggested.
Abstract: The variations in the compressive strength, splitting, and flexural-tension strengths, and the modulus of elasticity of concrete are reviewed, and representative probability distributions are suggested The effects of volume, rate of loading, and in-situ casting of concrete are included
280 citations
TL;DR: In this paper, the complete set of elastic mechanical properties for graphite-epoxy fiber-reinforced materials at any fiber-volume fraction by modifying equations previously developed to include transversely isotropic graphite fiber properties is demonstrated by using these equations to curve fit elastic-property data obtained ultrasonically over a range of fiber volume fractions.
Abstract: This paper demonstrates that it is possible to calculate the complete set of elastic mechanical properties for graphite-epoxy fiber-reinforced materials at any fiber-volume fraction by modifying equations previously developed to include transversely isotropic graphite-fiber properties. Experimental verification of the modified equations is demonstrated by using these equations to curve fit elastic-property data obtained ultrasonically over a range of fiber-volume fractions. Material systems under consideration are T300/5208, AS-3501 and Modomor II/LY558 graphite epoxy. Using the modified equations it is possible to extrapolate for fiber properties. From Modomor II/LY558 ultrasonic data, it is shown that five out of seven extrapolated graphite-fiber properties are consistent with the assumption that graphite fibers are transversely isotropic. Elastic properties for T300/5208 and AS-3501 are ultrasonically evaluated by propagating stress waves through six individual specimens but at various angles from a block of unidirectional material. Particular attention is devoted to specimen dimensions. To demonstrate the need for accurately calculating or experimentally measuring all lamina elastic properties, a brief discussion is included on the effect that variations in lamina elastic properties have on calculating interlaminar stresses.
173 citations
TL;DR: In this article, the effect of aggregate concentration on the strength and modulus of concrete in both uniaxial tension and compression has been investigated, and the results suggest that the strength of cement paste in tension and in compression is reduced by the addition of 20% by volume of graded aggregate, falling to a minimum value at a volume fraction of 30 to 35%.
Abstract: Synopsis The paper presents details of art investigation into the effect of aggregate concentration upon the strength and modulus of elasticity of concrete in both uniaxial tension and uniaxial compression. The test results relate to cement paste and to mixes containing 20 to 80% by volume of a graded aggregate. Emphasis was placed on accurate determination of the specific gravity and absorption of the constituent aggregate size fractions in an attempt to maintain a constant free water Icement ratio in the various mixes. The specimens were continuously rotated during the setting period in order to minimize settlement of the aggregate particles. The results suggest that the strength of cement paste in tension and in compression is reduced by the addition of 20% by volume of graded aggregate, falling to a minimum value at a volume fraction of 30 to 35% and then increasing with further addition of aggregate. In contrast, the modulus in tension and in compression increases with the addition of aggregate and t...
161 citations
TL;DR: In this paper, the properties of compatible glassy polyblends based on poly(2.6-dimethyl-1,4-phe nylene oxide) (PPO) were investigated.
Abstract: The mechanical behavior of compatible glassy polyblends based upon poly(2.6-dimethyl- 1,4-phe nylene oxide) (PPO) was investigated. In particular, the influence of composition, molecular weight, and molecular weight distribution upon the tensile modulus of the blend was assessed. Various possible correlations between the experimentally determined moduli and theory are considered. Included are correlations with density, packing density, composite theory, and lattice fluid theory. The modeling of the properties of mixtures via Simplex lattice design is also presented. Finally, attention is given to the development of compatibility criteria based upon tensile modulus and density measurements.
96 citations
TL;DR: The incremental modulus H is proposed as a suitable parameter describing arterial elasticity under in vivo circumstances and implies that the classical formula of the isotropic Young's modulus introduced by Bergel for arteries is not applicable to incremental deformations.
76 citations
TL;DR: Fiber optic acoustic sensors with composite structures have been analyzed and shown to offer greatly increased acoustic sensitivity as discussed by the authors, where the composite structure consists of an optical fiber coated with or embedded in an elastic material of lower elastic modulus.
Abstract: Fiber optic acoustic sensors with composite structures are analyzed and shown to offer greatly increased acoustic sensitivity. The composite structure consists of an optical fiber coated with or embedded in an elastic material of lower elastic modulus. Sensitivity increases of 10–100 times are indicated. Important advantages of this technique in practical acoustic sensors are also described.
75 citations
TL;DR: In this paper, a mathematical model was presented for the transmission of airborne noise through the walls of an orthotropic cylindrical shell, and parameters were varied to see how orthotropicity affected noise transmission.
64 citations
Patent•
03 Aug 1979
TL;DR: Improved bone connective prostheses are disclosed in this paper, where a reinforcement element carrying a polymer layer having varying modulus of elasticity is carried by the prosthesis and the interior surface of the polymer layer is attached to the reinforcement element.
Abstract: Improved bone connective prostheses are disclosed. The prostheses comprise a reinforcement element carrying a polymer layer having a varying modulus of elasticity. The exterior surface of the polymer layer constitutes the bone attachment surface of the prostheses and has the lowest modulus of elasticity. The interior surface of the polymer layer is attached to reinforcement element and has the highest modulus of elasticity. Portions of the polymer layer lying between the exterior and the interior surface of the polymer layer have moduli of elasticity which are intermediate with respect to the moduli of elasticity of the exterior and interior surface of the layer. The modulus of elasticity of the layer decreases in the direction of interior to exterior. The decrease in modulus of elasticity may be either continuous or incremental. The reinforcement element may have either a simple or a complex structure.
56 citations
TL;DR: In this paper, an experimental investigation and a theoretical analysis of the behavior of a quartz crystal microbalance with coatings of varying viscosity and modulus of elasticity are presented. And the analysis is based upon the analogy with electrical waves propagating in a lossy transmission line.
Abstract: Presented is an experimental investigation and a theoretical analysis of the behaviour of a quartz crystal microbalance with coatings of varying viscosity and modulus of elasticity. The analysis is based upon the analogy with electrical waves propagating in a lossy transmission line.
50 citations
TL;DR: In this paper, the elastic properties of hot-pressed samples with an addition of 5 wt% MgO were studied and three different methods of measurement were used, operating in the frequency range 20 kHz to 10 MHz.
Abstract: Silicon oxynitride is a refactory material which appears to exhibit good mechanical and thermal properties. This work studies the elastic properties of hot-pressed samples with an addition of 5 wt% MgO. The samples are isotropic and homogeneous, and the three different methods of measurement used, operating in the frequency range 20 kHz to 10 MHz, give similar results. Young's modulus and shear modulus are low (about 22×1010 Pa and 9×1010 Pa, respectively), which leads to small thermal stresses and thus allows a good thermal shock resistance. The elastic moduli decrease linearly when the porosity increases over the range of 0 to 27%. Poisson's ratio is sensibly a constant equal to 0.2, and the rate of variation is the same for both moduli: 2.5, this value being superior to what could be expected from the usual theories.
TL;DR: In this article, the effects of thermal spikes on the moisture absorption characteristics, the ultimate tensile strength, and the buckling modulus of Thornel 300/Fiberite 1034 composites were evaluated.
Abstract: Tests were performed evaluating the effects of thermal spikes on the moisture absorption characteristics, the ultimate tensile strength, and the buckling modulus of Thornel 300/Fiberite 1034 composites. Measurements were made on unidirectional and π/4 laminates, using different types of thermal spikes. A survey was also made of the existing data. This survey, together with the present data indicate how thermal spikes affect the mois ture absorption and the mechanical properties of different graphite-epoxy composites.
TL;DR: In this paper, a comparison of experimental data for zero strain Young's modulus of uniform density thermoplastic foam for short times has been made with several theoretical and empirical correlations.
Abstract: A comparison of experimental data for zero strain Young's modulus of uniform density thermoplastic foam for short times has been made with several theoretical and empirical correlations. An analysis of the variance of the data with the predicted values from the many models indicated that the simplistic density squared relationship adequately described the modulus of the foam for basic engineering calculations.
TL;DR: In this paper, the authors measured the velocities of longitudinal and transversal waves and calculated the values of elasticity, shear modulus, and Poisson's ratio for some expanded clays.
01 Feb 1979
TL;DR: In this paper, the properties of a well documented, carefully prepared SMC-R50 composite over a temperature range of - 40 degree C to 121 degree C were reported. And the properties determined include Young's modulus, shear modulus and Poisson's ratio.
Abstract: Materials scientists and design engineers considering the use of composites molded from sheet molding compound (SMC) for structural applications need reliable mechanical property data for these composites. In response to this need, the mechanical properties of a well documented, carefully prepared SMC-R50 composite over a temperature range of - 40 degree C to 121 degree C are reported. The properties determined include Young's modulus, shear modulus, and Poisson's ratio, thermal coefficient of expansion, tensile fatigue, tensile creep, and ultimate strengths in tension, compression, shear and flexure. All tests are based on one composite material, thus, conclusions about the relationship between different mechanical properties can be made. For example, the tensile and compressive moduli of SMC-R50 composite are virturally the same. Also, Young's modulus, shear modulus, and Poisson's ratio obey an established equation relating these constants. In addition, this study establishes the existence of a fatigue limit for SMC-R50 composite.
TL;DR: The analysis of underground oil-shale recovery processes requires knowledge of the mechanical properties of oil shale at various temperatures The tensile strength, compressive strength, and Young's modulus are of special importance The variation of these properties with temperature is important in assessing the strength of underground columns and confining walls for process cavities as discussed by the authors.
Abstract: The analysis of underground oil-shale recovery processes requires knowledge of the mechanical properties of oil shale at various temperatures The tensile strength, compressive strength, and Young's modulus are of special importance The variation of these properties with temperature is important in assessing the strength of underground columns and confining walls for process cavities This work presents the results of an experimental study to quantify this temperature dependence It was found that both tensile and compressive strength of oil shale show a marked decrease in strength as temperature is increased, for a given richness At a given temperature, both the tensile and compressive strengths decrease as richness increases, although the rate of decrease diminishes at richnesses of about 42 gal/ton and above Equations have been developed to permit estimates of the various paramters involved The Young's moduli estimated show a considerable decrease with temperature At 400/sup 0/F, the modulus is reduced to 60% of its room temperature value for 192-gal/ton shale in tension (23 refs)
TL;DR: The present state of knowledge of this latter set of properties is reviewed and an attempt is made to interpret them with respect to the application of dental composite filling materials.
Abstract: The traditional parameters used to evaluate dental composites in the laboratory have been working time, polymerization contraction, compressive, tensile, shear, and bond strength, resistance to indentation, water sorption and solubility, leakage, color stability by the 24-hour ultraviolet lamp test, and thermal coefficient of expansion. Other less well documented properties of composites are their modulus of elasticity, abrasive wear, wetting by water or saliva, and staining. It is the purpose of this paper to review the present state of knowledge of this latter set of properties and to attempt to interpret them with respect to the application of dental composite filling materials.
01 Jan 1979
TL;DR: In this paper, a frusto-conical laminated elastomeric bearing is provided wherein at least some of the layers are graded in composition so that they have a relatively high modulus of elasticity at the inner circumstance, a second lower but still relatively high elasticity in the outer circumference, and a third still lower modulus in an intermediate position between the inner and outer circumferences, with the grading being arranged so as to provide an optimum balance of strain distribution and spring rates consistent with bearing lifetime and reduced-torque considerations.
Abstract: A frusto-conical laminated elastomeric bearing is provided wherein at least some of the layers are graded in composition so that they have a first relatively high modulus of elasticity at the inner circumstance, a second lower but still relatively high modulus of elasticity at the outer circumference, and a third still lower modulus of elasticity in an intermediate position between the inner and outer circumferences, with the grading being arranged so as to provide an optimum balance of strain distribution and spring rates consistent with bearing lifetime and reduced-torque considerations.
Patent•
27 Jun 1979
TL;DR: In this paper, a durable, outer air seal structure capable of long term, reliable service in a gas turbine engine environment is disclosed, which is built around a porous, low modulus pad of metallic material which is disposed between the ceramic material and a substrate of solid metallic material.
Abstract: A durable, outer air seal structure capable of long term, reliable service in a gas turbine engine environment is disclosed. Various construction details which enable the incorporation of high temperature tolerant ceramic materials into the outer air seal structure are developed. The structure is built around a porous, low modulus pad of metallic material which is disposed between the ceramic material and a substrate of solid metallic material. The ceramic material is applied to a preferred density at which the physical properties of modulus of elasticity (E), mean tensile strength (T), coefficient of thermal expansion (α) and thermal conductivity (K) impart good thermal shock resistance, erosion resistance and abradability characteristics to the seal structure.
TL;DR: In this paper, the propagation constants of an extensional acoustic wave are determined by exciting one end of a strip of material while the other end is suspended under constant tension. But the results are limited to a frequency range of 100 Hz to 40 kHz, depending on the extensional wave velocity and attenuation.
Abstract: A progressive wave apparatus featuring an automated data processor is described. The apparatus accurately determines the propagation constants of an extensional acoustic wave by exciting one end of a strip of material while the other end is suspended under constant tension. The apparatus is capable of making measurements in the frequency range of 100 Hz to 40 kHz, depending on the extensional wave velocity and attenuation in the material. As illustrations of the technique, measurements were made on several rubber compounds of different polymer type and compounding ingredients. Extensional sound speed, attenuation, modulus, and loss factor were determined over a frequency range of 1–10 kHz and a temperature range of 4°–47°C. Applying the time‐temperature superposition principle to the data, master curves were constructed and WLF shift constants were determined. The apparatus was found to be a fast and reliable method to determine the dynamic viscoelastic constants.
Journal Article•
01 Jan 1979
TL;DR: In this article, the compressive strength, modulus of elasticity, and stress-strain relationships of concrete at elevated temperatures were investigated and a review of published results provided information for the development of upper and lower bound relationships for compressive and elasticity and established exposure conditions for a lower bound thermal response.
Abstract: A study is presented concerning the compressive strength, modulus of elasticity, and stress-strain relationships of concrete at elevated temperatures. A review of published results provides information for the development of upper and lower bound relationships for compressive strength and the modulus of elasticity and establishes exposure conditions for a lower bound thermal response. The relationships developed from the literature review are confirmed by the results of a verification test program. The strength and elasticity relationships provide a basis for the development of design stress-strain curves for concrete exposed to elevated temperatures.
01 Jan 1979
TL;DR: In this paper, the transverse rupture strength (TRS), ultimate compressive strength (UCS), and Young's modulus of elasticity (E) in tension and compression have been measured.
Abstract: Polycrystalline diamond compacts are important tools for new material-working techniques such as turning difficult-to-cut materials, drilling, and wire drawing. Consequently, the properties of such materials are needed to formulate their proper use. This paper deals with the measurement of the mechanical properties of synthetic diamond compacts and other hard materials, both synthetic and natural. The transverse rupture strength (TRS), ultimate compressive strength (UCS), and Young’s modulus of elasticity (E) in tension and compression have been measured. Density and resistivity were also obtained.
TL;DR: Some current suggestions for the modulus of elasticity are collated and a further analysis for values on the assumption of an orthotropic left ventricle is presented.
Abstract: The determination of numerical values for the elasticity of the myocardium is a prerequisite for any accurate analysis of the left ventricle. Such values as are normally quoted are for a modulus of elasticity for an isotropic homogeneous model. Here some current suggestions for the modulus of elasticity are collated and a further analysis for values on the assumption of an orthotropic left ventricle is presented.
TL;DR: In this article, a study of autoclaved (216° C) cement-fly ash mixtures containing 50% fly ash (by weight) was conducted and a linear correlation for modulus of elasticity of the porous solid and the composition term, 2 -C/S + A−kF, was also obtained for each water-solid ratio.
Abstract: Nine different fly ashes have been used in a study of autoclaved (216° C) cement-fly ash mixtures containing 50% fly ash (by weight). Paste samples for each fly ash were prepared at water-solid ratios of 0.22 to 0.45 and mechanical property-porosity relations were determined. The autoclaved products were characterized by several techniques. Linear correlations with a composition term, C/(S + A)−kF, were obtained for logarithms of zero-porosity modulus of elasticity and microhardness values. A linear correlation for modulus of elasticity of the porous solid and the composition term, 2 - C/S + A−kF, was also obtained for each water-solid ratio. Correlations for microhardness of the porous solid with a composition term, 2−C/S + A are reported, a different curve for each water-solid ratio. Impregnation of the porous products resulted in increased values for modulus of elasticity and microhardness and provided an alternate means of estimating zero-porosity values of these properties.
Patent•
26 Jul 1979
TL;DR: In this paper, a frusto-conical laminated elastomeric bearing is provided wherein at least some of the layers are graded in composition so that they have a relatively high modulus of elasticity at the inner circumference, and a relatively low modulus at the outer circumference, with the grading being arranged so as to provide an optimum balance of strain distribution and spring rates consistent with bearing lifetime and reduced-torque considerations.
Abstract: A frusto-conical laminated elastomeric bearing is provided wherein at least some of the layers are graded in composition so that they have a first relatively high modulus of elasticity at the inner circumference, and a second relatively low modulus of elasticity at the outer circumference, with the grading being arranged so as to provide an optimum balance of strain distribution and spring rates consistent with bearing lifetime and reduced-torque considerations.
01 Jan 1979
TL;DR: In this article, the longitudinal Young's modulus and major Poisson's ratio of a unidirectional, short-fiber composite are found in terms of the fiber volume fraction and the tip-to-tip spacing of the fibers.
Abstract: Based on a composite-cylinder model with a short cylindrical fiber embedded in the center of a cylindrical matrix, the longitudinal Young's modulus and major Poisson's ratio of a unidirectional, short-fiber composite are found in terms of the fiber volume fraction and the tip-to-tip spacing of the fibers. The expressions obtained are then modified to account for the influence of volume fraction and aspect ratio of the fibers. These results, together with Christensen and Waals' normalized expressions, are used to calculate the Young's modulus and Poisson's ratio of a randomly-oriented chopped-fiber composite in terms of the fiber volume fraction and its aspect ratio. The theory developed is then applied to examine numerically the effects of fiber length on the Young's modulus and Poisson's ratio of short glassfiber/polyester-resin composites. The results show that the Young's modulus of both unidirectional and randomly-oriented fiber composites are strongly dependent on the fiber length; so is the Poisson's ratio, though to a lesser degree.