Showing papers on "Orthotropic material published in 1978"
TL;DR: In this article, a mathematical and computational capability has been developed for calculating the effective mechanical properties of three-dimensional periodic truss-like structures, and two models are studied in detail.
Abstract: A mathematical and computational analysis capability has been developed for calculating the effective mechanical properties of three-dimensional periodic truss-like structures. Two models are studied in detail. The first, called the octetruss model, is a three-dimensional extension of a two-dimensional model, and the second is a cubic model. Symmetry considerations are employed as a first step to show that the specific octetruss model has four independent constants and that the cubic model has two. The actual values of these constants are determined by averaging the contributions of each rod element to the overall structure stiffness. The individual rod member contribution to the overall stiffness is obtained by a three-dimensional coordinate transformation. The analysis shows that the effective three-dimensional elastic properties of both models are relatively close to each other.
124 citations
TL;DR: In this paper, a simple approximate formula for the natural frequencies of flexural vibration of isotropic plates, originally developed by Warburton using characteristic beam functions in Rayleigh's method, is modified to apply to specially orthotropic plates and extended to include the effect of uniform, direct inplane forces.
101 citations
TL;DR: The material constants identified show the orthotropic elastic moduli of the lumbar intervertebral disc to be independent of segment level but decrease directly as a function of the severity of degeneration.
73 citations
01 Jan 1978
55 citations
TL;DR: In this article, an expression for the transmission loss by finite, viscoelastic and orthotropic multilayered plates, based on a combination of statistical and deterministic approaches, is presented.
50 citations
TL;DR: In this article, a variational displacement formulation for multilayered plates is used to verify the continuity of displacements and shear stresses at the interfaces of a simply supported plate, and the equations of motion and natural boundary conditions remain unchanged in form regardless of the number of layers.
48 citations
TL;DR: In this paper, a hollow orthotropic elastic cylinder due to a steady-state plane temperature distribution T(r,θ) is analyzed for traction-free boundary conditions, and exact solution using the Airy stress function in a Fourier-series form is developed.
Abstract: Stresses in a hollow orthotropic elastic cylinder due to a steady-state plane temperature distribution T(r,θ) are analyzed for tractionfree boundary conditions An exact solution is developed using the Airy stress function in a Fourier-series form Numerical results are given for a fiber-reinforced composite material
37 citations
TL;DR: In this article, the problem of determining the stress and displacement fields in an orthotropic elastic strip containing a Griffith crack situated symmetrically and oriented in a direction normal to the edges of the strip is considered.
35 citations
TL;DR: In this article, a numerical analysis parametric study was conducted to determine the stress and strain states within an idealized soil specimen enclosed by a wire-reinforced rubber membrane and tested in the Norwegian Geotechnical Institute (NGI) simple shear apparatus.
Abstract: A numerical analysis parametric study was conducted to determine the stress and strain states within an idealized soil specimen enclosed by a wire-reinforced rubber membrane and tested in the Norwegian Geotechnical Institute (NGI) simple shear apparatus. The computations were performed utilizing a finite-element program applicable to three-dimensional elastic analysis of nonaxisymmetrically loaded axisymmetric solids. Orthotropic membrane elements were incorporated in the program to simulate the action of the wire-reinforced rubber membrane. A total of 14 cases was analyzed using different combinations of material properties, membrane stiffness, specimen geometry, and boundary displacements. In general, for the values of the parameters studied, the uniformity of shear strain distribution improves as (1) the specimen height-to-diameter ratio is decreased, (2) the percent of wire-reinforcement is increased, (3) the elastic modulus of the soil decreases, (4) the Poisson's ratio of the soil decreases, and (5) the applied horizontal displacement is increased.
33 citations
TL;DR: In this paper, a non-homogeneous material is designed to yield an optimum internal stress field for two dimensional problems in polar coordinates, with detailed results given for the problems of the pressurized, thick-walled cylinder and the rotating disk subjected to centrifugal body forces.
31 citations
TL;DR: In this paper, the effect of curvature and polar orthotropy on nonlinear dynamic behavior of a shallow spherical shell is investigated and numerical solutions based on an assumed two-term modeshape for the axisymmetric, forced (uniform pressure) and free vibrations are obtained for different shell geometries and orthotropic material constants.
TL;DR: In this article, a solution based on a one-term mode shape, for the large amplitude vibrations of a rectangular orthotropic plate, simply supported on all edges or clamped on all corners for movable and immovable in-plane conditions, is found by using an averaging technique that helps to satisfy the inplane boundary conditions.
TL;DR: In this paper, the authors developed an equation for predicting and sliding modes of crack growth along planes of geometric symmetry in viscoelastic orthotropic media with and without large prestrains.
TL;DR: In this article, the results of plate buckling analyses performed by means of the BENST module of the PLANS system of finite element structural analysis programs are presented, which involve a wide variation in laminate orthotropic and material axis orientation and a number of plate aspect ratios and support conditions.
TL;DR: In this article, a stability analysis based on the Finite Strip Method is presented for skew orthotropic plates subjected to in-plane loadings, where the straight sides of the plate are simply supported and the other two skewed sides are supported with any combination of fixed, free and simply supported boundaries.
TL;DR: In this paper, the buckling behavior of single orthotropic plates with certain boundary conditions can be related to that of an equivalent isotropic plate in terms of a single parameter involving the principal plate rigidities.
Abstract: The local buckling of structural sections composed of isotropic plate elements is well documented. It is the purpose of this paper to extend this work to include sections composed of orthotropic plates. It has been shown that the buckling behaviour of single orthotropic plates with certain boundary conditions can be related to that of an equivalent isotropic plate in terms of a single parameter involving the principal plate rigidities. It is proposed to investigate whether this principle may also be applied to the structural buckling problem. It has been shown that simple approximations to the deflected form of buckled plates can be used to give fast and reasonably accurate results for the plate buckling problem using an energy method. If these simple deflection functions are used in an energy analysis for structural sections then large errors may be introduced.
TL;DR: In this article, a finite element method is presented for the analysis of the vibratory characteristics of laminated orthotropic cylinders, which is capable of treating a three-dimensional initial stress state which is radially symmetric.
TL;DR: In this article, the title problem is solved using polynomial approximations and a weighted residuals approach, and a very simple, yet accurate, approximate fundamental frequency equation can be generated.
TL;DR: In this paper, a method of identification of material behavior parameters using a plate bending test is presented, and a number of results concerning the choice of numerical algorithm, the experimental protocole (number and locations of test points, loading) and the sensitivity of the method on experimental errors are presented.
Abstract: The paper presents a method of identification of material behaviour parameters. The method is applied to a simple example: the identification of orthotropic parameters using a plate bending test. A number of results are presented concerning the choice of numerical algorithm, the experimental protocole (number and locations of test points, loading) and the sensitivity of the method on experimental errors.
TL;DR: In this article, a method for analyzing tall framed buildings based on the concept of equivalent elastic membrane is presented, where the elastic properties of the membrane are evaluated taking into account the effects of finite size joints and axial deformations in the columns.
Abstract: A method for analyzing tall framed buildings based on the concept of equivalent elastic membrane is presented. The elastic properties of the membrane are evaluated taking into account the effects of finite size joints and axial deformations in the columns. Floors are assumed to be rigid in plane. The equivalent membrane is then analyzed using two-dimensional plane stress, specially orthotropic finite elements. The displacements thus obtained represent directly those of the actual structure, and the member forces are determined by integrating the corresponding stress components in the membrane. Two multistory multibay frames were analyzed, and the results show that a high degree of accuracy can be obtained with significantly smaller number of unknowns than by the exact and other simplified methods. The present technique can be readily applied to the static and dynamic analysis of tubed structures, clad multistory frames, and shear wall and frames structures.
TL;DR: In this paper, a numerical method for separation of stresses in photo-orthotropic elasticity using the numerical solution of compatibility equation for orthotropic case is proposed. But the accuracy of the numerical method and its application to practical problems are illustrated with examples.
Abstract: A numerical method is suggested for separation of stresses in photo-orthotropic elasticity using the numerical solution of compatibility equation for orthotropic case. The compatibility equation is written in terms of a stress parameter S analogous to the sum of principal stresses in two-dimensional isotropic case. The solution of this equation provides a relation between the normal stresses. The photoelastic data give the shear stress and another relation between the two normal stresses. The accuracy of the numerical method and its application to practical problems are illustrated with examples.
TL;DR: In this paper, the basic function satisfying boundary conditions along two opposite edges in one direction of the plate and then using suitable transformation, the plate bending equation is reduced to an ordinary differential equation.
TL;DR: In this article, Wu and Vinson investigated the effects of transverse shear and rotatory inertia on the large-amplitude vibration of orthotropic rectangular plates, based on assumed expressions not only for the mode shape w but also for the rotation components a and j3.
Abstract: Introduction T HE large-amplitude vibrations of plates and shells have been receiving considerable attention in the literature in recent years. In particular, rectangular plates have received the attention of many investigators. The results reported so far do not, in many cases, seem to incorporate the effects of transverse shear and rotatory inertia, Wu and Vinson investigated the effects of transverse shear and rotatory inertia on the large-amplitude vibration of isotropic, transversely isotropic, and orthotropic rectangular plates, based on assumed expressions not only for the mode shape w but also for the rotation components a. and j3. The purpose here is to suggest an improvement to the solutions given by Wu and Vinson by altogether eliminating a and 6 from the governing equations, thereby avoiding the necessity to proceed on assumed approximations for a. and /?. The equations developed here are based on Berger approximation. Based on Galerkin's method and an assumption of only mode shape w, the effects of geometric nonlinearity, transverse shear deformation, and rotatory inertia are reported for certain cases of isotropic and orthotropic rectangular plates clamped along the boundaries,
TL;DR: In this paper, two orthotropic model materials with unidirectional and bidirectional glass fiber reinforcement in polyester resin have been developed for photoelastic analysis and allied applications.