Showing papers in "Computer Methods in Applied Mechanics and Engineering in 1978"

TL;DR: In this paper, a new definition of rotations is introduced, called semitangential rotations, which leads to a reformulation of the theory of Ziegler [1,2] which is clearly consistent and correct.

TL;DR: In this article, a modified version of the variational method of Trefftz was presented for plate bending in which the coordinate functions satisfying the nonhomogeneous Lagrange equation were defined on subregions.

TL;DR: In this paper, a general formulation for geometrically nonlinear analysis of shells using very simple flat finite elements is described, based on the updated Langrangian description of motion (co-rotational coordinates).

TL;DR: In this article, a sensitivity analysis method is developed and demonstrated on a variety of static and dynamic structures and on vibration and impact absorbers, where direct numerical comparisons are possible, the method is shown to be five to ten times faster than methods previously employed.

TL;DR: This example indicates that for some mechanical engineering optimization problems, using the multicriterion optimization approach, the authors can automatically obtain a solution which is optimal and acceptable to the designer.

TL;DR: In this article, the authors analyzed the effect of wave reflection in a one-dimensional grid of finite elements whose size if uniform from element to element except at one node, using complex variables.

TL;DR: In this article, the stiffness matrix for a rectangular laminated anisotropic shallow thin shell finite element is derived under linear thin shell assumptions, where the assumed displacement state over the middle surface of the shell is expressed as products of one-dimensional first-order Hermite interpolation polynomials.

TL;DR: This paper reviews some recent developments in direct time integration methods for nonlinear structural dynamics that pertain to the use of linear multistep difference operators in conjunction with the pseudo-force approach.

TL;DR: In this article, the numerical solution of the Navier equations discretized by finite elements is studied by various forms of pre-conditioned conjugate gradient methods, and the dependence of the number of iterations is examined as a function of Poisson's ratio.

TL;DR: In this paper, an assessment of the incremental solution methods for the analysis of inelastic rate problems is presented, in which the possibilities of the initial load method are explored to improve the accuracy and stability of the traditional explicit operators by higher-order time expansions and implicit weighting schemes.

TL;DR: An electromagnet with constant interpolar field is designed by the techniques of optimal control discretized with Lagrangian triangular finite elements of degree 1.

TL;DR: Following an analysis of the boundary layer behaviour of the continuous problem, L -splines are introduced, and, by studying their behaviour for coarse meshes, they are able to modify the original schemes to produce so-called “disconnected” finite element methods.

TL;DR: In this article, an incremental total Lagrangian formulation is presented which allows the calculation of arbitrarily large displacements and rotations, and the derivation of the tangential stiffness as well as some remarks concerning its efficient programming are given.

TL;DR: In this article, a method of coupling between finite elements and integral representation is described, where the numerical scheme is obtained by means of a finite element discretization of a continuous variational problem.

TL;DR: In this paper, a new class of hybrid finite element methods for the numerical analysis of second-order elliptic boundary value problems is presented, characterized by the use of particular solutions of the differential equation being solved, in contrast to conventional hybrid methods in which polynomial approximations are used.

TL;DR: Conservative for coefficient matrices are found which are similar to Jacobian linearization and which reduce the computational work of various implicit schemes for the Euler equations of inviscid fluid flow.

TL;DR: In this article, a generalization of the Prager-Nagtegaal superposition principle for the optimal plastic design of structures subject to more than two alternate loads is presented.

TL;DR: In this paper, a finite element method for incompressible deformation is formulated from the virtual work equation based on deviatoric quantities, where the incompressibility constraint is imposed on the admissible displacement field by direct elimination of nodal displacements.

TL;DR: In this paper, Taylor series expansions about a generic point for stress resultants and couples, identically satisfying plate equilibrium equations, are derived for the transverse shear stiffness of laminated anisotropic shells.

TL;DR: In this article, a finite element capability which permits the analyst to vary the order of polynomial approximation over each finite element is discussed with reference to its potential for application to stress intensity factor computations in linear elastic fracture mechanics.

TL;DR: In this paper, the authors present necessary theorems and details for numerical computation of sensitivity matrices for spatially discretized structural systems subjected to dynamic excitation, and explicit numerical examples illustrate the methodology applied to multi-story shear frames whose force-displacement relationship is bilinear hysteretic.

TL;DR: In this article, the integrated force method of analysis is extended to calculate frequencies of structures, using the hitherto unexplored concept of "force mode shapes" as the prime variables in vibration analysis.

TL;DR: In this article, a numerical code is built up with 36000 cards and 343 subroutines to investigate the interconnected fields of velocity, temperature, pressure and isotope concentration in a gas centrigue.

TL;DR: The Galerkin method with an expansion of B -splines is used to solve Burgers' equation from an initial state involving a discontinuity in the space domain this article, which avoids the necessity of having a fine resolution knot distribution over the whole spatial domain in order to achieve an accurate solution.

TL;DR: This paper suggests the use of only the minimal covering that is sufficient for convergence in the discretized system and suggests the possibility of considerable economy in the cost of obtaining finite element solutions to complex problems, e.g. coupled field problems, three-dimensional problems, stress concentration etc.

TL;DR: In this paper, three problems of structural optimization are formulated and solved either by a direct or an iterative method, and the most general problem concerns cost-optimization of perfectly plastic structures for alternative loads and the second and third ones are more specific problems with linear objective functions, quadratic yield conditions and either a single or several load conditions.

TL;DR: In this paper, the basic elastic and geometric stiffness properties of the individual supporting columns are synthesized into a stiffness matrix compatible with an axisymmetrical shell element by a series of transformations, to be used in conjunction with a finite element representation of the cooling tower.

TL;DR: In this paper, the potential of using numerical simulation methods for predicting and interpreting aerodynamic phenomena affecting bluff bodies is explored in a general way, and the limitations of this scheme are discussed in detail, together with some suggestions for extensions that could be realized in the immediate future.

TL;DR: In this article, the authors describe the application of a numerical procedure to the computation of the hydrodynamics and heat/mass transfer processes for the shearing flow of a fluid over a wavy boundary.