Showing papers on "Young's modulus published in 1981"
Journal Article•
TL;DR: In this paper, the applicability of linear elastic fracture mechanics to concrete and similar materials is analysed by use of the Fictitious Crack Model, where the fracture zone in front of a crack is represented by a fictitious crack able to transfer stress.
Abstract: A calculation model (the Fictitious Crack Model), based on fracture mechanics and the finite element method, 1s presented. In the model the fracture zone in front of a crack is represented by a fictitious crack that 1s able to transfer stress. The stress transferring capability of the fictitious crack normally decreases when the crack width increases. The applicability of linear elastic fracture mechanics to concrete and similar materials is analysed by use of the Fictitious Crack Model. It" Is found that linear elastic fracture mechanics 1s too dependent on, among other things, specimen dimensions to be useful as a fracture approach, unless the dimensions, for concrete structures, are in order of meters. The usefulness of the J-integral, the COD-approach and the R-curve analysis is also found to be very limited where cementitious materials are concerned. The complete tensile stress-strain curve is introduced as a fracture mechanical parameter. The curve can be approximatively determined if the tensile strength, the Young's modius and the fracture energy are known. Su1table~lest methods Tor determining" TRise~~/'Voerties are presented and test results are reported for a number of concrete qua! » a. A new tyr * very stiff tensile testing machine Is presented by which it is possible to carry r . itable tensile tests on concrete. The complete tensile stress-strain curves h •«• feen determined for a number of concrete qualities. The thesi' overs a complete system for analysing crack propagation in concrete as it Include* -ealistic material model, a functional calculation model and methods for determiv" «/ the material properties necessary for the calculations. Therefore this work oi r t to be of use as a base for further studies of the fracture process of concrete < i similar materials.
897 citations
154 citations
TL;DR: In this article, the average internal stress measured by the cantilever method was 5 x 108N m−2 compression, and the dependence of the size of the wrinkles on the film thickness was deduced and compared with experimental results.
109 citations
TL;DR: For stainless steels 304, 310, and 316, longitudinal and transverse ultrasonic velocities were measured by a pulse-echo method between 295 and 4 K as mentioned in this paper, and five elastic constants were computed: longitudinal modulus, shear modulus and Young's modulus.
Abstract: For stainless steels 304, 310, and 316, longitudinal and transverse ultrasonic velocities were measured by a pulse‐echo method between 295 and 4 K. From these velocities were computed five elastic constants: longitudinal modulus, shear modulus, Young’s modulus, bulk modulus, and Poisson’s ratio. All three steels show low‐temperature elastic‐constant anomalies, which arise from magnetic phase transitions.
103 citations
01 May 1981
55 citations
TL;DR: In this article, a new method using zone drawing and zone annealing has been studied to prepare high-modulus and high-strength PET fiber, and the experimental procedure consists of two stages: Zone drawing and Zone Annealing, where the zone drawing was done on the original as-spun fiber to produce a fiber with as high an orientation and as low a crystallinity as possible.
Abstract: To prepare high-modulus and high-strength PET fiber, a new method using zone drawing and zone annealing has been studied. The apparatus used for this method is the usual tensile tester equipped with a band heater 2 mm wide and a sample holder which can apply a high tension to the fiber. The experimental procedure consists of two stages: zone drawing and zone annealing. The zone drawing was done on the original as-spun fiber in order to produce a fiber with as high an orientation and as low a crystallinity as possible. The zone-drawn fiber was subsequently zone annealed under high tension by moving the band heater from one end to the other of the fiber at a temperature above the crystallization temperature at a considerably low moving speed. In spite of the simple apparatus and procedure, Young's modulus of the fiber obtained was 19.4 × 1010 dyn/cm2, which is comparable to the maximum value of the high-tenacity PET filament commercially available. In order to elucidate the change in the superstructure with zone drawing or zone annealing, optical, x-ray, IR, DSC, and dynamic mechanical measurements were performed. It is suggested that the zone-annealed fiber consists of almost perfectly oriented crystallites and fully extended amorphous chains.
50 citations
TL;DR: In this paper, it was shown that the in-plane shear modulus and Poisson's ratio of paper can be predicted with reasonable accuracy if the Young's moduli of the paper in the machine and cross directions are known.
44 citations
Patent•
02 Mar 1981
TL;DR: In this paper, a method of producing a vibration damping and sound absorbing coating on a rigid substrate is provided in which method a first coating of a viscoelastic material having after gelling a modulus of elasticity of 5×10 6 to 5x10 8 dynes/cm 2 is sprayed onto the substrate whereafter there is spraying onto said first coating a second coating, which after geling a second layer having after having a higher modulus, being at least 10 times greater than that of the first layer.
Abstract: A novel method of producing a vibration damping and sound absorbing coating on a rigid substrate is provided in which method a first coating of a viscoelastic material having after gelling a modulus of elasticity of 5×10 6 to 5×10 8 dynes/cm 2 is sprayed onto the substrate whereafter there is sprayed onto said first coating a second coating of a viscoelastic material having after gelling a modulus of elasticity of 5×10 7 to 5×10 9 dynes/cm 2 , the modulus of elasticity of said second outer coating being at least 10 times greater than that of said first coating.
44 citations
01 Jul 1981
39 citations
TL;DR: In this paper, the distribution of density and tensile properties in quenched modified poly(phenylene oxide) specimens was investigated, and the profiles were obtained using the layer removal technique, which was found not to affect the measured properties.
Abstract: The distribution of density and tensile properties in quenched modified poly(phenylene oxide) specimens was investigated. Quenching was carried out from temperature level above Tg to below Tg temperatures. Simultaneous to buildup of residual stresses, profiles of density and tensile properties were observed. The profiles were obtained using the layer removal technique, which was found not to affect the measured properties. Quenching of the material results in a steep density gradient in the surface layers. Correspondingly, the tensile modulus increases significantly from the surface to the inner layers and so are also the ultimate tensile properties. This behavior could be accounted for neither by the conventional packing volume approach nor by superposition of internal and external stresses. However, observations of the fracture surfaces are very supportive and indicate that the fracture initiation sites are influenced by the residual stresses. Hence, the mechanical behavior is strongly affected by both density and residual stresses profile. Density is the controlling factor in determining the elastic properties whereas residual stresses determine the ultimate strength and fracture mechanism.
34 citations
TL;DR: In this article, an experimental method is described to calculate both shear and Young's moduli of composite materials by three-point bending, which includes appropriate corrections for certain extraneous effects.
Abstract: An experimental method is described to calculate both shear and Young's moduli of composite materials by three-point bending. The proposed procedure includes appropriate corrections for certain extraneous effects. The importance of the two basic ratios, E/G, which is an indicator of the degree of anisotropy of the material, and L/d, the span-to-depth ratio, is underlined.
Patent•
26 Nov 1981
TL;DR: In this article, an adhesive-sheet for the reinforcement of metal plate, and a method of reinforcing metal plates using an adhesive sheet, are described, where the adhesive sheet comprises a first epoxy resin composition layer and a second epoxy resins composition layer laminated thereon, and when cured by heating, it has a modulus of elasticity in tension sufficient to increase the stiffness of the metal plate.
Abstract: An adhesive-sheet for the reinforcement of metal plate, and a method of reinforcing metal plates using an adhesive-sheet, are described. The adhesive-sheet comprises a first epoxy resin composition layer and a second epoxy resin composition layer laminated thereon wherein the first epoxy resin composition layer, when cured by heating, has a modulus of elasticity in tension sufficient to increase the stiffness of the metal plate, whereas the second epoxy resin composition layer, when cured by heating, has a modulus of elasticity in tension insufficient to increase the stiffness of the metal plate.
TL;DR: In this paper, two-dimensional analytical elastic models are developed for evaluating dynamic characteristics, namely natural frequencies and modes of vibration of a wide class of earth dams in a direction parallel to the dam axis.
Abstract: Two-dimensional analytical elastic models are developed for evaluating dynamic characteristics, namely natural frequencies and modes of vibration of a wide class of earth dams in a direction parallel to the dam axis In these models the non-homogeneity of the dam materials is taken into account by assuming a specific variation of the stiffness properties along the depth (due to the continuous increase in confining pressure) In addition, both shear and normal (axial) deformations are considered Cases having constant elastic moduli, linear and trapezoidal variations of elastic moduli, and elastic moduli increasing as the one-half, one-third, two fifths, and a general (l/m)th powers of the depth are studied Dynamic properties of three real earth dams in a seismically active area (Southern California) estimated from their earthquake records (input ground motion and crest response in the longitudinal direction) as well as results from full-scale dynamic tests on one of these dams (including ambient and forced vibration tests) are compared with those from the suggested models It was found that the models in which the shear modulus and the modulus of elasticity of the dam material vary along the depth are the most appropriate representations for predicting the dynamic characteristics The agreement between the experimental and earthquake data and the theoretical results from some of the models is reasonably good
TL;DR: In this article, a study was made on the stress relaxation behavior at 25 C of poly(methyl methacrylate) in uniaxial tension as a function of physical aging at both room temperature and 60 C.
Abstract: A study was made on the stress relaxation behavior at 25 C of poly(methyl methacrylate) in uniaxial tension as a function of physical aging at both room temperature and 60 C. Test specimens were compression molded at 165 C, then quenched to room temperature and allowed to age for up to 30 days prior to testing. Stress relaxation curves measured after different aging times could be superposed to a single master curve for each aging temperature. Superposition was achieved by applying vertical and horizontal shifts. Hence, the shape of the response curves was not changed by aging. This is in accordance with observations made by Struik for tensile creep curves. Volume changes as a function of physical aging were also determined. Simple exponential relationships were observed between volume and both horizontal and vertical shifts. The horizontal shift implies a shift in the effective time scale caused by a change in free volume. The vertical shifts could be correlated with changes in Young's modulus caused by a change in density. For the range of aging studied, the response time scale varied over nearly two decades of log-time. For the same conditions modulus varied by 30 percent.
TL;DR: In this article, a non-resonance technique with bidirectional strain gauges was used to measure various storage moduli and damping factors of glassy polymers in the frequency range 10 −2 to 10 −7 Hz.
TL;DR: In this paper, the components of the complex tensile modulus E∗, Poisson's ratio v∗, shear modulus G∗ and bulk modulus K∗ have been determined at 21°C in the frequency range 10−2 to 107 Hz for PMMA and rigid PVC.
TL;DR: In this paper, the effects of the irradiation treatments on the breaking stress and Young's modulus were studied by a three point bending test, and the effects were small; both electron radiation up to 5000 Mrad and gamma radiation upto 350 Mrad resulted in slight increases in both stress and modulus.
Abstract: Epoxy/graphite fiber, polyimide/graphite fiber, and polysulfone/graphite fiber composites were exposed to 1.33 Mev gamma irradiation and 0.5 Mev electron bombardment for varying periods of time. The effects of the irradiation treatments on the breaking stress and Young's modulus were studied by a three point bending test. Effects were small; both electron radiation up to 5000 Mrad and gamma radiation up to 350 Mrad resulted in slight increases in both stress and modulus.
Patent•
27 Jul 1981
TL;DR: An optical fiber transmission cable has a prestressed reinforcement which has a tensile modulus of (4-6)×106 psi, a flex modulus and a thermal coefficient of linear expansion of approximately 2.8×10-6 /°F as mentioned in this paper.
Abstract: An optical fibre transmission cable has a prestressed reinforcement which has a tensile modulus of (4-6)×106 psi, a flex modulus of (1.0-5.7)×106 psi and a thermal coefficient of linear expansion of approximately 2.8×10-6 /°F. and comprises a glass fibre roving saturated with synthetic resin material and held under tension by the synthetic resin material. The reinforcement and an optical fibre are provided within a synthetic resin material sheathing and the reinforcement provides the required mechanical reinforcement properties without introducing electrically conductive material into the cable. A method of making the reinforcement and the cable is also disclosed.
TL;DR: In this paper, 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: In this paper, a hollow cylinder testing device was used to measure the radial deformation along the inner and outer surfaces of the specimen, which enabled the determination of the modulus of elasticity and Poisson's ratio (v) of the tested soils.
Abstract: This investigation describes the development of a hollow cylinder testing device and the feasibility of using this equipment for determining the tensile properties of compacted cohesive soils. Hollow cylinder tests were conducted on compacted specimens of Vicksburg buckshot clay (CH), Vicksburg lean clay (CL), and a sandy clay mixture (SC) from DeGray Dam. Unconfined compression tests and indirect tension tests were also conducted to provide comparative compressive properties of the materials. With this hollow cylinder testing device it is possible to measure the radial deformation along the inner and outer surfaces of the specimen; these measurements enable the determination of the modulus of elasticity (E) and Poisson's ratio (v) of the tested soils. The ratio of tensile modulus to the compression modulus, as determined by hollow-cylinder and unconfined compression tests, ranges from 2.6 to 4.4. On the other hand, approximately equal Poisson's ratio values were measured by hollow-cylinder and unconfined compression tests. Based upon results of this experimental program, the hollow cylinder test is judged to provide a reasonably accurate method for measuring the tensile properties of compacted soils.
TL;DR: In this paper, a structural model of low density ( −3 ) cellular plastics based on an aggregate approach is presented, specifically designed to quantify the modulus anisotropy arising from uniaxial cellular orientation.
TL;DR: The flexure modulus of standard stainless steel orthodontic wires was determined by the use of an iterative finite element technique to be 25.4 x 10(6) psi (175 x 10 (3) MN/m2) as mentioned in this paper.
Abstract: The flexure modulus of elasticity of standard stainless steel orthodontic wires was determined by the use of an iterative finite element technique to be 25.4 x 10(6) psi (175 x 10(3) MN/m2). This technique accounts for the configurational changes in the test specimens due to the relatively large deflection during the cantilever test. Under these conditions, the elementary strength of materials relationships does not accurately describe the flexure characteristics of the wires.
TL;DR: In this article, the frequency range where the approximate Love theory gives good approximation and its accuracy in that range are determined, and the differences between the apparent and actual values depend on the lateral dimension to wavelength ratio and on the complex elastic constants as well.
TL;DR: In this article, the Young's modulus was measured for in-situ formed Cu-Nb wire composites containing 7.5 and 15.0 vol% niobium filaments, and the experimental results indicated that most of the enhancment in the annealed composites originates from the thermally induced elastic strains at the matrix-filament interfaces.
Abstract: Measurements of the Young’s modulus are reported for in‐situ formed Cu‐Nb wire composites containing 7.5 and 15.0 vol.% niobium filaments. Comparison of the experimental values for the as‐drawn and annealed wires shows rapidly diverging trends with decreasing wire diameter. In composites with the smallest filaments (50–200 A) the modulus increases by almost 100% upon annealing and exceeds the maximum values calculated from bulk elastic constants. However, plastic strain (in elongation) of as little as 0.02% results in a substantial (∼25%) reduction in modulus, suggesting that most of the enhancment in the annealed composites originates from the thermally induced elastic strains at the matrix‐filament interfaces.
Journal Article•
TL;DR: In this article, the dynamic bulk modulus, K d, of several fiber types was measured by the acoustic-impedance technique and the values of K d obtained at different densities were in excellent agreement with van Wyk's theory of fibre-mass compression.
Abstract: An investigation is reported in which the dynamic bulk modulus, K d, of several fibre types was measured by the acoustic-impedance technique. The values of K d obtained at different densities are in excellent agreement with van Wyk's theory of fibre-mass compression.
TL;DR: In this paper, the glass transition pressure Pg for a polyurethane elastomer (Solithane 113, 50/50 resin-catalist ratio, manufactured by Thiokol Chemical Co.) is located at 2.5 kbar at room temperature and glass transition temperature Tg is at −20 °C.
Abstract: The glass transition pressure Pg for a polyurethane elastomer (Solithane 113, 50/50 resin‐catalist ratio, manufactured by Thiokol Chemical Co.) is located at 2.5 kbar at room temperature and the glass transition temperature Tg is at −20 °C. Mechanical behavior of the elastomer, namely the tensile and the compressive stress‐strain behavior, in the glassy state as well as in the rubbery state has been determined. The Young’s modulus increases from ∼107 dyn/cm2 in the rubbery state to ∼1010 dyn/cm2 in the glassy state. The tensile fracture strain increases rapidly from 60% at atmospheric pressure to greater than ∼200% at 1 kbar and higher. In the glassy state, the samples exhibit yielding, yield drop, and cold drawing. The yield drop is not accompanied by necking. Rather the samples undergo uniform drawing throughout the entire gage length. A series of sequential loading, unloading, and reloading tests in the plastic range was also conducted in the glassy state. It was observed that the plastic strain recove...
TL;DR: In this paper, the authors examined the relationship among thermal behavior, crystallinity, orientation and modulus of nylons-6 and 6,6 and reported that the extent of both crystallinity and draw play an important role in the enhancement of modulus.
TL;DR: In this paper, the authors examined the deformation of high density polyethylene at an extrusion draw ratio of 30 over a range of temperatures and pressures, and found that the extrusion rate was feasible in a pressure range beyond which fractures occurred owing to strain rate and shear or tensile failure.
Abstract: The crystalline state deformation of high density polyethylene has been examined at an extrusion draw ratio of 30 over a range of temperatures and pressures. The experiments involve combined pushing (extrusion) and pulling through a conical die. The pressure dependence of the extrusion rate through conical dies is given by a logarithmic relation and the temperature dependence by an activation energy of ∼95 kcal/mole. An equation established for the total applied force linearly relates the pulling and extrusion pressure components and represents a force balance at the die entrance and exit. Steady-state extrusion, with or without pulling, was feasible in a pressure range beyond which fractures occurred owing to strain rate and shear or tensile failure. Under some circumstances the extrusion rate was increased by ten times. The mechanical properties and mode of deformation were not affected by pull load and fibers with a tensile modulus of 55 GPa were produced at T < 110°C.