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Direct stiffness method
About: Direct stiffness method is a research topic. Over the lifetime, 2584 publications have been published within this topic receiving 53131 citations.
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TL;DR: In this article, a modeling technique based on the direct stiffness method (DSM) was proposed to describe the behavior in time of composite beams with partial shear interaction accounting for creep and shrinkage of the slab.
Abstract: This paper presents a modelling technique based on the direct stiffness method (DSM) to describe the behaviour in time of composite beams with partial shear interaction accounting for creep and shrinkage of the slab. The time-dependent behaviour of the concrete is modelled using algebraic representations, such as the age-adjusted effective modulus method and the mean stress method, while the steel joist, the reinforcement and the shear connection are assumed to behave in a linear-elastic manner. Only one discretization (i.e. in the time domain) is required by the proposed stiffness formulations to perform a time analysis, while two discretizations (i.e. one in the time domain and the other in the spatial domain along the beam axis) are required by other modelling techniques available in the literature. The ability of the derived elements to overcome curvature locking problems observed to occur in some conventional displacement formulations is also highlighted. The proposed DSM approach is then validated against analytical solutions derived by the authors for simple structural systems. The applicability of this method for the time analysis of continuous composite beams is also illustrated. Copyright © 2008 John Wiley & Sons, Ltd.
35 citations
TL;DR: An analytical solution for the inelastic response of an arbitrarily layered concentric cylinder assemblage under axial shear loading of the type that produces homogeneous deformation in an equivalent homogenized medium is presented in this paper.
34 citations
TL;DR: An extension of the finite-element displacement method to the analysis of linear bifurcation buckling of general shells of revolution under static axisymmetric loading is presented in this article, where the shell is discretized into either a series of conical frusta or of frusta with meridional curvature.
Abstract: An extension of the finite-element displacement method to the analysis of linear bifurcation buckling of general shells of revolution under static axisymmetric loading is presented. A systematic procedure for the formulation of the problem is based upon the criterion that the condition for neutral stability of a system is the vanishing of the second variation of the total potential energy from the stable equilibrium state to the perturbed bifurcation state; this results in an eigenvalue problem. For solution, the shell is discretized into either a series of conical frusta or of frusta with meridional curvature. The prebuckling equilibrium solution is axisymmetric, but the perturbation-displacement field within each element is represented by Fourier circumferential components of the generalized displacements which are defined at the nodal circles. The present formulation is applied to a number of shells of revolution with arid without meridional curvature, and comparisons are made with other theoretical and available experimental results.
34 citations
TL;DR: In this article, an approach has been developed that uses optimization methods to automate wind-tunnel model design, which can be divided into separate stiffness design and mass design stages, and a sample structure was manufactured and subjected to static and modal testing using laser holographic techniques.
Abstract: Wind-tunnel model design can be very involved, so an approach has been developed that uses optimization methods to automate it. The model design process has been divided into separate stiffness design and mass design stages. Then, a sample structure was manufactured and subjected to static and modal testing using laser holographic techniques. The predicted flutter response of the model matches the predicted flutter response of the full-scale wing very closely. Nomenclature c = element of calculated flexibility matrix F = objective function g = constraint K = stiffness matrix k = proportionality constant M = mass matrix m = total mass x = element of eigenvector matrix 8 = element of target flexibility matrix a) = natural frequency
34 citations
TL;DR: In this paper, an efficient free-vibration analysis procedure of two-dimensional structures was developed by employing a discretization technique based on a recently developed concept of finite dynamic elements, involving higher order dynamic correction terms in the associated stiffness and inertia matrices.
Abstract: The paper develops an efficient free-vibration analysis procedure of two-dimensional structures. This is achieved by employing a discretization technique based on a recently developed concept of finite dynamic elements, involving higher order dynamic correction terms in the associated stiffness and inertia matrices. A plane rectangular dynamic element is developed in detail. Numerical solution results of free-vibration analysis presented herein clearly indicate that these dynamic elements combined with a suitable quadratic matrix eigenproblem solution technique effect a most economical and efficient solution for such an analysis when compared with the usual finite element method.
34 citations