Showing papers in "International Journal of Solids and Structures in 1968"

TL;DR: In this paper, a study of the linear theory of elasticity in which the potential energy-density depends on the gradient of the strain in addition to the strain was performed, and the relations connecting the stresses in the three forms and the boundary conditions in three forms were derived.

TL;DR: In this article, the theory of a new family of isoparametric elements for use in two-dimensional situations is described, and examples illustrating the accuracy improvement are included in the paper.

TL;DR: In this article, the authors extended the classical theory of piezoelectricity to accommodate an electro-mechanical interaction in centrosymmetric (including isotropic) materials and a surface energy of deformation and polarization.

TL;DR: In this article, a more compact scheme is presented for building the stiffness matrix of a finite plate element in bending. But this scheme requires the element to be of a conforming type, which guarantees continuity of deflections and slopes at the interfaces.

TL;DR: Boundary and continuity conditions for cylindrical shell under nonlinear flexural vibrations, discussing modal approximations for equations of motion are discussed in this article, where the authors also consider the effects of nonlinear vibrations.

TL;DR: A new formulation for the title problem, based on a fundamental solution of the equations of linear elasticity theory is described and exploited in this article, which is applicable without inherent restriction as to number, shape, and material composition of the inclusions which are embedded, in general, in a finite material matrix.

TL;DR: In this paper, the elastic buckling and initial postbuckling behavior of clamped shallow spherical shells under concentrated load is considered and it is found that bifurcation into an asymmetric deflection pattern will occur before axisymmetric snap-buckling unless the ratio of the shell rise to the thickness lies within a narrow range corresponding to relatively thick shells.

TL;DR: In this paper, a simple displacement function for the flexure of triangular plate elements has been used for calculating frequencies and buckling loads of plates, and reasonably good stability predictions may be made using quite coarse element subdivisions.

TL;DR: It is finally proved that a general completeness criterion, of order not higher than the highest order of derivative entering into the energy density expression, can take up any constant value within the element, is a sufficient condition for convergence even if conformity is not achieved.

TL;DR: In this article, an approximate numerical analysis procedure is presented which is capable of solving thin shells of arbitrary shape, boundary conditions and loading, idealized as an assemblage of triangular finite elements representing both membrane and flexural stiffness properties.

TL;DR: In this article, an interaction theory which takes account of slip, uplift and friction effects is formulated without, as in existing theories, assuming equal curvatures of the interacting elements, and two simultaneous differential equations connecting the uplift tension arising from differential deflexions of the two elements with the axial force within each of the elements are solved by a finite-difference approach.

TL;DR: In this paper, the basic relations of the acoustoelasticity are deduced by means of the infinitesimal wave propagation in a deformed isotropic elastic material.

TL;DR: In this paper, the authors apply basic ideas and methods of continuum mechanics to the crack propagation process and apply them to the case of fatigue and fluctuation cracks in elastic and rigid-plastic solids.

TL;DR: A general form of perturbation analysis for discrete non-linear structural systems is presented in this article, which generates a system of linear equations which can be solved sequentially for the path derivatives in the unloaded state.

TL;DR: In this article, a dual formulation to the usual compatible element model is proposed to provide bounds on the exact solution of a finite element problem, and a suitable equilibrium model for use in a routine manner in the finite element scheme.

TL;DR: In this paper, a minimum-weight design of a sandwich member that has to serve as a tie in some circumstances and as a beam in others is used to illustrate a general method of optimal design of sandwich structures that have to meet several design requirements.

TL;DR: In this paper, the theory of the triangular equilibrium model is presented, which is a revised version of that of [3], taking advantage of oblique co-ordinates, and it is also extended to cover transverse loading modes.

TL;DR: In this article, a mixed variational theorem for linear orthotropic thermoelastic solids is presented, where the mechanical state variables are taken to be the displacement vector and a scalar stress variable.

TL;DR: The two-dimensional problem of equilibrium of a perfectly elastic body with couple-stresses is considered in this article, where the general form of solution of the problem in the case of an orthotropic medium is given.

TL;DR: In this paper, modified variational principles are established that impose less exacting continuity conditions on the relevant fields, and the application of the principles to typical finite-element analyses is indicated, according to the number of independent fields that are involved.

TL;DR: In this article, the plane-strain problem of an orthogonal elastic wedge, one face of which is subjected to arbitrary shearing tractions in the absence of other loads, is treated both within classical elastostatics and within a linear theory of elastic behavior that takes into account the influence of couple-stresses.

TL;DR: In this paper, a one-dimensional structure with segmentwise constant specific stiffness is considered and a sufficient condition for optimality is established and its use is illustrated by an example, where the number of segments of constant specific stiffness is given, but their boundaries and specific stiffnesses are to be determined to minimize the structural weight.

TL;DR: In this article, the fundamental frequency of a Bernoulli-Euler beam with variable cross-section is optimized with respect to its fundamental frequency for a set of homogeneous boundary conditions.

TL;DR: In this paper, the linearized theory of an elastic Cosserat surface is discussed emphasizing its relevance to the classical problem of the linear theory of elastic shells (and plates) regarded as three dimensional bodies.

TL;DR: The generalized pyramidal failure criterion is shown to be a convenient criterion for describing the state of stress under which isotropic materials will yield or undergo brittle fracture as mentioned in this paper, which is useful for very complex materials, but it is believed that most materials can be adequately described by simple variants of the general criterion.

TL;DR: In this paper, a theory for the small deformations superposed on the large deformation of an elastic rod is given, and some aspects of material and geometrical symmetry are discussed.

TL;DR: In this paper, a general method of solution is presented with the help of which one can satisfy exactly arbitrary boundary conditions prescribed on the curved and flat surfaces of a hollow or solid cylinder of any length.

TL;DR: In this paper, the stability of symmetric structural systems with first and second order imperfections is investigated, and the analysis concerns a discrete system with n degrees of freedom, and expressions relating reduction in critical load to the magnitude of the imperfections indicate that a complex interaction exists between these quantities.

TL;DR: In this paper, conditions are established ensuring the continuous dependence on the initial data of the equilibrium solution and certain other classes of solution to the elastodynamic initial boundary value problem and the method of proof depends upon logarithmic convexity arguments and is notable for the absence of any definiteness condition on the elasticities.

TL;DR: In this article, nonlinear constitutive equations for a mixture of two elastic solids are discussed and relations between certain of the material constants related to each constituent and the corresponding constants associated with the mixture are determined.