Showing papers on "Elasticity (economics) published in 1983"
TL;DR: In this article, the integropartial differential equations of the linear theory of nonlocal elasticity are reduced to singular partial differential equations for a special class of physically admissible kernels.
Abstract: Integropartial differential equations of the linear theory of nonlocal elasticity are reduced to singular partial differential equations for a special class of physically admissible kernels. Solutions are obtained for the screw dislocation and surface waves. Experimental observations and atomic lattice dynamics appear to support the theoretical results very nicely.
3,929 citations
TL;DR: In this paper, the authors review the analysis of composite materials from the applied mechanics and engineering science point of view, including elasticity, thermal expansion, moisture swelling, viscoelasticity, conductivity, static strength, and fatigue failure.
Abstract: The purpose of the present survey is to review the analysis of composite materials from the applied mechanics and engineering science point of view. The subjects under consideration will be analysis of the following properties of various kinds of composite materials: elasticity, thermal expansion, moisture swelling, viscoelasticity, conductivity (which includes, by mathematical analogy, dielectrics, magnetics, and diffusion) static strength, and fatigue failure.
2,216 citations
Book•
01 Mar 1983466 citations
TL;DR: In this paper, Sumner et al. proposed a method to estimate the level of monopoly power in the cigarette industry by observing the change in marginal cost and price of a product and inferring the elasticity of demand perceived by the firm.
Abstract: In a recent article in this Journal, Sumner (1981) took an ingenious approach to estimating the level of monopoly power in the cigarette industry. He noted that differences in marginal costs exist in the industry due to varying levels of state taxes. The sales prices established will satisfy the equation p[I + (lIq)l = MR = MC, where p = price and -q = the elasticity of demand for the product in question. If elasticity is a constant, observing the change in marginal cost and the change in price enables one to infer the elasticity of demand perceived by the firm. Elasticity could then be used as a proxy for the firm's market power. This technique turns out to be of very limited applicability, however, because it is extremely sensitive to the functional form assumed for the demand curve. Consider the general problem of a firm facing constant marginal costs of c. In maximizing profits the firm solves
293 citations
TL;DR: In this article, it was shown that the Cosserat continuum, which admits additional degrees of freedom associated with rotation of the microstructure, describes the foam more accurately than the classical continuum.
Abstract: The rigidity of rods of a polymeric foam in bending and torsion is measured as a function of diameter. The dependence of rigidity upon specimen size is found to be inconsistent with a classically viscoelastic continuum model. The Cosserat continuum, which admits additional degrees of freedom associated with rotation of the microstructure, describes the foam more accurately than the classical continuum. Evidence is presented that additional degrees of freedom associated with the deformation of the microstructure, must be incorporated in a complete continuum model of foamed materials.
187 citations
157 citations
TL;DR: An analysis of steady flow of blood in cat's lung based on a set of actual data on anatomy and elasticity and the effect of the vessel elasticity embodied in the "fifth-power law" and the "sheet-flow" theory.
Abstract: Recently, a complete set of data on the branching pattern of the cat's pulmonary arterial and venous trees and the elasticity of these blood vessels was obtained in our laboratory. Hence it becomes...
117 citations
TL;DR: In this paper, an algorithm for the numerical analysis of a highly nonlinear variational inequality encountered in the study of contact problems with non-classical friction laws is described, and numerical results obtained for a representative example problem are given.
66 citations
TL;DR: In this article, the predictions of several entanglement models of rubber elasticity for the uniaxial stress-strain response of crosslinked polymer networks are examined, and it is found that the Gaylord tube model and the Flory constrained junction fluctuation model both agree well with the experimental data.
62 citations
01 Jan 1983
TL;DR: In this paper, an isothermal elastohydrodynamically-lubricated rectangular contact was evaluated numerically, where the elasticity and Reynolds equations were simultaneously solved by solving the simultaneous solution of elasticity, load, and material parameters.
Abstract: An isothermal elastohydrodynamically lubricated rectangular contact was evaluated numerically. This required the simultaneous solution of the elasticity and Reynolds equations. In the elasticity analysis the contact zone was divided into equal rectangular areas, and it was assumed that a uniform pressure was applied over each area. The elastohydrodynamic lubrication theory thus developed was used to investigate the influence of the dimensionless speed, load, and materials parameters on minimum film thickness. Ten cases were used in obtaining the minimum film thickness formula. Plots are shown that indicate the details of the pressure distribution, film shape, and flow. The characteristic pressure spike is clearly in evidence as is the parallel film shape through the central portion of the contact, with a minimum film thickness occurring near the outlet of the contact.
59 citations
TL;DR: In this article, the elasticity problem for a long hollow circular cylinder containing an axisymmetric circumferential crack subjected to general nonaxismmetric external loads is considered.
Abstract: The elasticity problem for a long hollow circular cylinder containing an axisymmetric circumferential crack subjected to general nonaxisymmetric external loads is considered. The problem is formulated in terms of a system of singular integral equations with the Fourier coefficients of the derivative of the crack surface displacement as density functions. The stress intensity factors and the crack opening displacement are calculated for a cylinder under uniform tension, bending by end couples, and self-equilibrating residual stresses.
TL;DR: In this paper, the Rayleigh-Plesset equation is modified by adding a new term to account for a normal force component caused by dilational elasticity of an adsorbed film.
Abstract: Adsorption films’ mechanical properties are discussed. With regard to a problem of bubble oscillations in a surfactant solution, dynamical boundary conditions at the bubble wall are modified by including a new term to account for a normal force component caused by dilational elasticity of an adsorbed film. Consequently, the Rayleigh–Plesset equation acquires a term which affects the restoring force of bubble oscillations. A linearized theory (for small‐magnitude oscillations) is developed which shows that the film dilational elasticity induces a change in the mean radius and a shift in the natural frequency of bubble oscillations. These effects become extremely important when a capillary component 2σ/R0 accounts for at least 20% of the total pressure inside the bubble.
TL;DR: In this article, the impact of carbon on current replacement surgery and some possibilities for future applications are described, as well as the potential of using carbon in orthopedic joint replacement surgery.
TL;DR: The flexure moduli of elasticity of solid and multi-stranded orthodontic wires were determined and the differences were statistically significant for the stainless steel, chromium-cobalt-nickel, and nickel-titanium alloys.
Abstract: The flexure moduli of elasticity of solid and multi-stranded orthodontic wires were determined. Results for the solid wires approximated their tensile values, but the differences were statistically significant for the stainless steel, chromium-cobalt-nickel, and nickel-titanium alloys. The flexure moduli of the multi-stranded wires ranged from 0.89 to 5.11 X 10(6) psi, and were dependent on the direction of activation.
Book•
01 Apr 1983
TL;DR: This paper presents a description of ThreGBP-Dimensional Elasticity and some Mathematical Aspects of Threedimensional elasticity as well as some of the aspects of threedimensional flexibility that have not yet been described.
Abstract: Avant-Propos.- 1 Description of ThreGBP-Dimensional Elasticity.- 2 Some Mathematical Aspects of Threedimensional Elasticity.- Bibliography, Comments and some Open Problems.- References.- List of notations.
TL;DR: In this article, the duree de service Nf depend de ces derniers et est importante en deformation elastique, de la reorientation des martensites et de la transformation pseudoelastique.
Abstract: Essais de fatigue sous contrainte uniaxiale et divers modes de deformation. La duree de service Nf depend de ces derniers et est importante en deformation elastique, de la reorientation des martensites et de la transformation pseudoelastique
TL;DR: In this paper, the authors introduce the notion of elasticity and present its main mathematical and graphical properties, illustrating them on real economic cases, such as the consumption of marijuana and the demand for hospital beds.
Abstract: The following pages introduce the notion of elasticity and present its main mathematical and graphical properties, illustrating them on real economic cases, such as the consumption of marijuana and the demand for hospital beds.
TL;DR: In this paper, the development of plane Couette flow for viscoelastic fluids is analyzed using a constitutive equation that can be obtained from molecular theory, in which the molecules are regarded as finitely extensible dumbbells.
Abstract: Unsteady-state development of plane Couette flow for viscoelastic fluids is analyzed using a constitutive equation that can be obtained from molecular theory, in which the molecules are regarded as finitely extensible dumbbells. Typical features of the flow situation are as follows: (i) For a fluid with moderate elasticity, not only stress overshoot but also velocity overshoot are predicted. (ii) For suitable combinations of elasticity and gap width, and for some time intervals stress propagation and reflection phenomena are predicted. (iii) After a sufficient time has elapsed, the stress state behaves similarly to that corresponding to the start-up of a steady simple shear flow.
TL;DR: In this paper, the methode de la dynamique moleculaire is used to determine the determination of l'amplitude moyenne de vibration θ and l'elasticite (module de cisaillement μ): les deux ont une variation logarithmique avec la dimension du systeme.
Abstract: Analyse par la methode de la dynamique moleculaire. Determination de l'amplitude moyenne de vibration θ et de l'elasticite (module de cisaillement μ): les deux ont une variation logarithmique avec la dimension du systeme. Quand θ≃0,18, les particules commencent a diffuser et l'elasticite est proche de sa valeur prevue pour la fusion. Ces resultats montrent que les modeles informatiques anterieurs sont trop reduits pour simuler un solide volumique pres de son point de fusion
TL;DR: In this paper, the elasticity of polyethylene fibres were crosslinked by means of 60Coγ-radiation and the equilibrium elasticity behavior of the thus obtained networks was studied.
Abstract: Ultra-high strength polyethylene fibres were crosslinked by means of60Coγ-radiation. The equilibrium elasticity behaviour of the thus obtained networks was studied. The elastic modulus of the dry network, from which the sol-fraction was extracted, was found to be 10 times larger than the modulus of the same network in the swollen state or in the dry state prior to the extraction. This effect, that could not be attributed to oxidative degradation, is explained by the presence of a large amount of pendant chains in the fibre-networks. In the melt, after removal of the sol-fraction, the pendant chains are thought to establish severe constraints on the network chains, resulting in an increment of the elastic modulus of the polyethylene network.
01 Jan 1983
TL;DR: In this paper, a general rheological model of a nonlinear viscoplastic solid is developed, affording better quantitative prediction of behavior of viscoplast materials, which are quantified in terms of three types of curves obtained by tests, commonly used for description of mechanical material properties.
Abstract: A general rheological model of a nonlinear viscoplastic solid is developed, affording better quantitative prediction of behavior of viscoplastic materials. Rheological properties are quantified in terms of three types of curves obtained by tests, commonly used for description of mechanical material properties: constant rate, force deformation, creep, and relaxation curves. The mathematical model is based on a characteristic nonlinear differential equation describing the mechanical properties of a material. This equation defines the force F acting on a test specimen as composed of a cubic elasticity force K0x+rx3, viscous damping force Cẋ, and internal friction force Ff (sgn ẋ). The elastic parameter K0 quantifies linear elasticity while the strain hardening (or softening when negative) parameter r affords prediction of nonlinear behavior of the material. The viscous and Coulomb damping forces properly account for both rate‐dependent and rate‐independent energy dissipative properties of the material. Local...