Showing papers on "Young's modulus published in 1980"
TL;DR: The experiment performed on 138 individuals revealed a diminished elasticity and stretchability after the age of 30, associated with an increase in the visco-elastic component.
Abstract: The mechanical properties of the in vivo dermis were measured by means of a torque applied to the skin. The resulting deformation of 2–6°, including the immediate and delayed visco-elastic components, as well as the relaxation were measured, and the raw values corrected for a constant skin thickness. The experiment performed on 138 individuals from 3 to 89 years old revealed a diminished elasticity and stretchability after the age of 30, associated with an increase in the visco-elastic component. The Young's modulus doubles with age. The results are discussed in terms of the various models proposed to explain dermal structure.
669 citations
TL;DR: A two-level hierarchical fibre-reinforced composite model is under development which appears to provide a much more suitable description of the behaviour of bone as a fibre- reinforcing composite material.
Abstract: Bonfield and Grynpas1 have compared their experimental data for Young's modulus of elasticity versus the angle of orientation of the specimen to the long axis of bone with a theoretical curve predicted from a calculation for fibre reinforced materials proposed by Currey2. As a result of the poor agreement between the two curves they conclude “… an alternative model is required to account for the dependence of Young's modulus on orientation” (ref. 1). Such an alternative has been under development in my laboratory for the past 8 years (refs 3–7). It is a two-level hierarchical fibre-reinforced composite model which appears to provide a much more suitable description of the behaviour of bone as a fibre-reinforced composite material.
227 citations
TL;DR: In this paper, the tensile behavior of blends of linear polyethylene (PE) and isotactic polypropylene (PP) was examined in relation to their morphology, showing that yield stress increases monotonically with increasing PP content, while true ultimate strength is much lower in all blends than in pure polymers as a result of early fracture.
Abstract: The tensile behavior of blends of linear polyethylene (PE) and isotactic polypropylene (PP) was examined in relation to their morphology. Yield stress increases monotonically with increasing PP content, while true ultimate strength is much lower in all blends than in the pure polymers as a result of early fracture. The blends fail at low elongation because of their two-phase structure, consisting of interpenetrating networks or of islands of PE in a PP matrix, as shown by scanning electron microscopy of fracture surfaces and transmission electron microscopy of thin films. While spherulites in PP are very large (∼100 μm in diameter), addition of 10% or more of PE drastically reduces their average size. This, together with the profusion of intercrystalline links introduced by PE, may be associated with maximization of tensile modulus in blends containing ∼80% PP. Introduction of special nucleating agents to PP reduces average spherulite size and is accompanied by slight improvements in modulus. Thin films of blends strained in the electron microscope neck and fibrillate in their PE regions, but fracture cleanly with little fibrillation in areas of PP.
162 citations
TL;DR: In this article, the authors measured longitudinal and transverse ultrasonic velocities in 20 samples acquired randomly and reported three kinds of variations for four elastic constants: sample to sample, directional within a sample, and repeated measurements on a single sample.
Abstract: Variability of elastic constants in stainless‐steel 304 was determined by measuring longitudinal and transverse ultrasonic velocities in 20 samples acquired randomly. Three kinds of variations—sample to sample, directional within a sample, and repeated measurements on a single sample—are reported for four elastic constants: the bulk modulus, Young’s modulus, shear modulus, and Poisson’s ratio. Because of surprisingly small variations, 1% or less, the principal problem became measurement sensitivity and reproducibility. To overcome this problem, a high‐resolution measurement system was devised using general‐purpose equipment augmented with a very simple impedance‐transforming amplifier and an FET transmission gate. With this system the often‐reported troublesome transit‐time correction disappeared. Effects due to frequency and directionality were negligible.
139 citations
TL;DR: In this article, the same range of resins were used as a matrix material for a series of composites reinforced with carbon, glass and aromatic polyamide fibres, and the composites were unidirectionally reinforced, having been manufactured by pultrusion, and were compression tested in the fibre direction.
Abstract: The compression behaviour of a series of polyester resins of various compositions and in different states of cure has been investigated. Their mechanical characteristics having been established, the same range of resins was then used as a matrix material for a series of composites reinforced with carbon, glass and aromatic polyamide fibres. The composites were unidirectionally reinforced, having been manufactured by pultrusion, and were compression tested in the fibre direction after a series of experiments to assess the validity of a simple testing procedure. “Rule of Mixtures” behaviour occurred in glass-polyester composites up to limiting volume fractions (V
f) of 0.31 for strength and 0.46 for elastic modulus, the compression modulus being equal to the tensile modulus, and the apparent fibre strength being in the range 1.3 to 1.6 GPa at this limiting V
f. At a V
f of 0.31 the strengths of reinforced polyesters were proportional to the matrix yield strength, σ
my, and their moduli were an inverse exponential function of σ
my. For the same matrix yield strength a composite with an epoxy resin matrix was stronger than polyester based composites. At V
f=0.30, Kevlar fibre composites behaved as though their compression modulus and strength were much smaller than their tensile modulus and strength, while carbon fibre composites were only slightly less stiff and weaker in compression than in tension. The compression strengths of the polyester resins were found to be proportional to their elastic moduli.
134 citations
TL;DR: In this article, an approximate theoretical treatment for detachment of an elastomer from a rigid spherical inclusion by a tensile stress applied to the elastomeic matrix is given.
Abstract: An approximate theoretical treatment is given for detachment of an elastomer from a rigid spherical inclusion by a tensile stress applied to the elastomeric matrix. The inclusion is assumed to have an initially-debonded patch on its surface and the conditions for growth of the patch are derived from fracture energy considerations. Catastrophic debonding is predicted to occur at a critical applied stress when the initial debond is small. The strain energy dissipated as a result of this detachment, and hence the mechanical hysteresis, are also evaluated. When a reasonable value is adopted for Young's modulus E of the elastomeric matrix, it is found that detachment from small inclusions, of less than about 0.1 mm in diameter, will not occur, even when the level of adhesion is relatively low. Instead, rupture of the matrix near the inclusion becomes the preferred mode of failure at an applied stress given approximately by E/2. For still smaller inclusions, of less than about 1 μm in diameter, rupture of the matrix becomes increasingly difficult, due to the increasing importance of a surface energy term. These considerations account for the general features of reinforcement of elastomers. Small-particle fillers become effectively bonded to the matrix, whereas larger inclusions induce fracture near them, or become detached from the matrix, at applied stress that can be calculated from the particle diameter, the strength of adhesion, and the elasticity of the matrix material.
127 citations
TL;DR: In this article, the nominal values for compressive strength, limits of elasticity (yield point), strain, elastic modulus and apparent density are reported for the cancellous bone of the femoral head and condyle.
Abstract: The time independent material behavior of cylindrical specimens obtained from the cancelous bone of 20 cadaveric human femora were determined. In this part of the publication, the nominal values for compressive strength, limits of elasticity (yield point), strain, elastic modulus and apparent density are being reported for the cancellous bone of the femoral head and condyle. The correlations between the various parameters are analysed. A positive linear correlation between the four parameters compressive stength, limit of elasticity, modulus of elasticity and apparent density could not be excluded. The material properties vary considerably both within one single bone and between individuals. Compressive strength, modulus of elasticity and apparent density found for cancellous bone of the femoral head are greater than those found in the condyles. Within the condyles, compressive strength, elastic modulus and apparent density increase from the proximal parts to the parts closer to the joint. The medial femoral condyle showed higher compressive strength than the lateral one. Relating each of the three other parameters to the apparent density of the individual specimen did not result in equalizing the data for the material properties. This indicates that the mechanical properties of cancellous bone are strongly related to the direction of loading.
117 citations
Journal Article•
TL;DR: In this article, a simple model was developed for calculating the mass loss of the material and the thickness of the char layer, and a technique was proposed for predicting material damage through the use of such correlations.
Abstract: The decrease in ultimate tensile strength, shear strength, tensile modulus, and shear modulus of fiber reinforced composites exposed to fire or to high temperature was investigated. A simple model was developed for calculating the mass loss of the material and the thickness of the char layer. The mass loss as well as the degradation in tensile and shear properties of Fiberite T300/1034 and Hercules AS/3501-6 graphite epoxy composites exposed to fire were measured. A correlation between the degradation in properties and the calculated mass loss and the char layer thickness was developed. A technique was proposed for predicting material damage through the use of such correlations.
113 citations
TL;DR: In this article, the nominal values for compressive strength, limits of elasticity (yield point), strain, elastic modulus and apparent density are reported for the cancellous bone of the femoral head and condyle.
Abstract: The time independent material behavior of cylindrical specimens obtained from the cancellous bone of 20 cadaveric human femora were determined. In this part of the publication, the nominal values for compressive strength, limits of elasticity (yield point), strain, elastic modulus and apparent density are being reported for the cancellous bone of the femoral head and condyle. The correlations between the various parameters are analysed. A positive linear correlation between the four parameters compressive stength, limit of elasticity, modulus of elasticity and apparent density could not be excluded. The material properties vary considerably both within one single bone and between individuals. Compressive strength, modulus of elasticity and apparent density found for cancellous bone of the femoral head are greater than those found in the condyles. Within the condyles, compressive strength, elastic modulus and apparent density increase from the proximal parts to the parts closer to the joint. The medial femoral condyle showed higher compressive strength than the lateral one. Relating each of the three other parameters to the apparent density of the individual specimen did not result in equalizing the data for the material properties. This indicates that the mechanical properties of cancellous bone are strongly related to the direction of loading.
93 citations
TL;DR: The role of the boundary interphase on the adhesion efficiency between fiber and matrix in the case of polymers reinforced with unidirectional fibers was investigated in this article, where a theoretical model was introduced considering that the composite material consists of three phases; that is, the fiber, the matrix and the interphase, material which is the part of the polymer matrix lying at the close vicinity of the fiber surface.
Abstract: The role of the boundary interphase on the adhesion efficiency between fiber and matrix in the case of polymers reinforced with unidirectional fibers was investigated. A theoretical model was introduced considering that the composite material consists of three phases; that is, the fiber, the matrix and the interphase, material which is the part of the polymer matrix lying at the close vicinity of the fiber surface. The interphase material, having different physical properties from those of the bulk matrix, affects the overall behavior of the composite. Moreover, the quality of adhesion between the two main phases depends greatly on the nature of the interphase material. In this study we have considered that the interphase material is inhomogeneous in nature, with properties varying continuously from the fiber surface to the bulk matrix. The theory developed resulted in a criterion of the adhesion quality and in a prediction of the longitudinal modulus of elasticity of the fiber-composite.
70 citations
TL;DR: In this paper, it was shown that simple relations exist between the elastic moduli of polycrystalline metals: G/E = a, G/B = b, and E/B= c. The values of the proportionality factors a, b and c for each individual type of crystal structure are different.
TL;DR: In this paper, an attempt has been made to correlate the uniaxial compressive strength and Young's modulus of gabbros and basalts with Schmidt hammer rebound number, the point load strength index, Is(50) and the degree of weathering.
Abstract: An attempt has been made to correlate the uniaxial compressive strength and Young's modulus of gabbros and basalts with Schmidt hammer rebound number, the point load strength index, Is(50) and the degree of weathering. Sixty three samples of gabbro and thirty of basalt from the ophiolitic complex of Pindos zone (Northern Greece) have been collected by core drilling and tested accordingly. The results have been processed using techniques from the statistical software SPSS. Some of the equations produced show relatively high correlation coefficients, all significant at a significance level higher than 95%. The equations establish reliable prediction models for the uniaxial compressive strength and modulus of elasticity of the above rock types by means of simple tests which can be carried out in the field.
Patent•
10 Jul 1980TL;DR: An artificial grass product with pile fibers having a modulus of elasticity from 25,000 p.i.s. to 100,000p.i and a moment of inertia of from 1.06×10-10 in. 4 to 8.33×10 -9 in 4.
Abstract: An artificial grass product with pile fibers having a modulus of elasticity of from 25,000 p.s.i. to 100,000 p.s.i. and a moment of inertia of from 1.06×10 -10 in. 4 to 8.33×10 -9 in 4 . For fibers of rectangular cross-section the fiber dimensions range from 0.004 in. to 0.010 in. in thickness and 0.020 in. to 0.100 in. in width.
TL;DR: In this paper, the variation of the elastic modulus as a function of different parameters characteristic of the latex was studied, and the amplitude of the vibrations of a latex sample was measured as the function of the frequency of excitation.
Abstract: Shear waves are excited in a latex sample. One detects the vibrations of the sample using light scattering phenomena (Kossel rings). The amplitude of vibrations of the latex sample, when recorded as a function of the frequency of excitation, presents a series of resonances. Analysis of the resonance peaks allows to determine the elastic modulus of the latex crystal. We study the variation of the elastic modulus as a function of different parameters characteristic of the latex.
TL;DR: In this article, the elastic moduli of several stabilized HfO/sub 2/ compositions were studied as functions of porosity and temperature, and it was proposed that oxygen-vacancy motion is the probable cause of this behavior.
Abstract: Elastic moduli of several stabilized HfO/sub 2/ compositions were studied as functions of porosity and temperature. Thermal expansion was also measured for one of the compositions. The modulus vs porosity and thermal-expansion measurements yielded typical relations. The modulus vs temperature measurements revealed an anomalous nonlinear relation between room temperature and 500/sup 0/C. Varying microstructural and testing conditions had no effect on the nonlinearity. Only the percent of stabilizer additive caused any change in this behavior. It is proposed that oxygen-vacancy motion is the probable cause of this behavior.
TL;DR: An ultrasonic pulse transit-time method was used to determine the Young'smodulus, shear modulus, and Poisson's ratio of seven anterior-restorative materials.
Abstract: An ultrasonic pulse transit-time method was used to determine the Young's modulus, shear modulus, and Poisson's ratio of seven anterior-restorative materials. Small rectangular specimens were immersed in a water bath and ultrasonic pulses propagated through them. Two types of ultrasonic wave could be generated inside the specimen by altering the angle of incidence. Measurement of the pulse transit-time for these two waves enabled their velocities and, hence, the material's elastic constants to be calculated. The variation of these properties with time of conditioning and temperature was also determined.
TL;DR: The kinetics of Young's modulus E during isothermal relaxation and crystallization of an all-metal glass Cu60Zr40 has been measured by a pulse-echo technique.
Abstract: The kinetics of change of Young’s modulus E during isothermal relaxation and crystallization of an all‐metal glass Cu60Zr40 has been measured by a pulse‐echo technique. E increases by about 10% between the as‐quenched and fully relaxed states. Crystallization of the glass produces a further 15% increase in E. The kinetics of the relaxation process can be fitted to an expression of the form ΔE=a ln t+b. a)On leave from the Institute of Physics, Saragevo, Yugoslavia.
TL;DR: Synthetic organic fibers with weight-basis tensile strengths five times as high as that of high strength steel wire and with a modulus of elasticity more than three times that of E-glass fiber are now available commercially.
Abstract: Synthetic organic fibers with weight-basis tensile strengths five times as high as that of high strength steel wire and with weight-basis tensile modulus of elasticity more than three times that of E-glass fiber are now available commercially (Table 1). The fibers are twice as strong and 10 to 20 times stiffer than the strongest synthetic fibers available previously, i.e. high strength nylon and polyester tire yarns (Table 1). High modulusjhigh strength aromatic fibers were discovered quite independently in the
TL;DR: In this article, the authors measured the alkaline durability of some alumino-silicate glasses containing Y2O3, La 2O3 and TiO2 by measuring the weight loss of the samples in 2N NaOH solution at 95°C as a function of time.
Abstract: Alkaline durability of some alumino-silicate glasses containing Y2O3, La2O3 and TiO2 was studied. The alkaline durability was determined by measuring the weight loss of the samples in 2N NaOH solution at 95°C as a function of time. It was found that these alumino-silicate glasses, which has very high elastic modulus, has very high alkaline durability, higher than that of zirconium containing glass. The observed alkaline durability depends on the amount of silica content; the lower the amount of silica, the higher the alkaline durability. The high alkaline durability of these glasses can be explained at least in part by the low solubilities of glass component oxides or its hydroxides. Y2O3 and La2O3 act as component to increase the both alkaline durability and elastic modulus, Al2O3 lowers the alkaline durability but increases the elastic modulus, and important for glass formation, and TiO2 appears to lower the total amounts of silica and alumina contents and expand the glass formation and indirectly increases the alkaline durability and also keeps the high modulus of elasticity.
01 Jan 1980
TL;DR: In this article, a functional relationship has been proposed describing the effect of moisture content on the modulus of elasticity of remoistened soybeans, based on experimental results, constants in the model have been determined by non-linear regression.
Abstract: A functional relationship has been proposed foi describing the effect of moisture content on the modulus of elasticity of remoistened soybeans. Based on experimental results, constants in the model have been determined by non-linear regression. Data from the ex-periments and the proposed function are graphically compared.
TL;DR: It is shown that the Young's modulus is a linear function of tissue water potential for a constant rate of strain.
Abstract: THE Young's modulus of potato tuber was studied A distinction was made between the apparent modulus measured in response to an applied strain and the actual modulus which was postulated to be a constant material property A theoretical analysis showed the two were related by the free energy present in tissue due to water It is shown that the Young's modulus is a linear function of tissue water potential for a constant rate of strain
TL;DR: In this paper, the changes in absolute values as well as in the temperature dependences of the elastic constants C11, C44, C′, and CL as a function of dissolved hydrogen up to 1.7 at.
Abstract: The changes in the absolute values as well as in the temperature dependences of the elastic constants C11, C44, C′, and CL as a function of dissolved hydrogen up to 1.7 at. %, in palladium single crystals have been determined. The measurements were performed in the temperature range between 140 and 310 K, using both longitudinal and shear 10‐MHz ultrasonic waves. In the α phase, the changes in the absolute values of the elastic constants C11, C44, and CL were very small, while a larger effect of −1.2%/ at. % H was obtained in the case of the shear constant C′. The relative changes in the computed bulk modulus and Voight‐Reuss average Young’s modulus in that phase are, respectively, +0.2% and −0.5%/ at. % H. The effects of hydrogen in the α phase on the temperature dependences of the elastic constants, however, are found to be significantly large in the case of C11 and CL and small in the case of the shear constants C′ and C44. These effects are discussed in terms of the volume expansion due to H in Pd, th...
TL;DR: In this article, measurements have been made on a modified pin-on-disc apparatus of the wear of metals sliding against a range of elastomers in the presence of a dispersion of abrasive particles in water.
TL;DR: In this paper, the authors measured Young's modulus of polycrystalline Nb3Sn between 4.2 and 300 K by static beam-deflection methods and observed marked softening.
Abstract: Ultrasonic measurements show that the shear modulus 1/2 (C11−C12) softens dramatically as single crystals of Nb3Sn approach the martensitic transition near 50 K. It is expected that Young’s modulus of polycrystals will also soften, but previous ultrasonic measurements, which suffer from severe damping, fail to show the expected effect. We have measured Young’s Modulus of polycrystalline Nb3Sn between 4.2 and 300 K by static beam‐deflection methods and observe marked softening. A value of 1.32×1012 dyn cm−2 was obtained at 300 K by the deflection of thin Nb3Sn‐Nb‐Nb3Sn composite strips by external stress. The variation of the modulus with T was obtained from the change in the radius of curvature of internally stressed Nb3Sn‐Nb composite strips. (This method is made possible by the near‐perfect match between the thermal expansion coefficients of Nb and Nb3Sn.) The modulus is found to be proportional to lnT between 50 and 300 K and is temperature independent below the superconducting Tc, resulting in a decre...
TL;DR: Young's modulus, the critical tensile stress, and the fracture stress of Stycast-1266 have been determined by the tension test as functions of temperature between room temperature and 2.2 K.
Abstract: Young’s modulus, the critical tensile stress, and the fracture stress of Stycast‐1266 have been determined by the tension test as functions of temperature between room temperature and 2.2 K.
TL;DR: Two dimensional finite element analyses were used to determine the direct tensile stress distributions along the lateral edge of the stem of the femoral component of a total hip replacement, and the two-dimensional model was found to be suitable for parametic studies.