Topic
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 paper, a method is presented to study the three-dimensional quasi-static response of a multi-layered poroelastic half-space with compressible constituents.
74 citations
TL;DR: In this article, it was shown that the Cartesian stiffness matrix associated with a linear elastic coupling between two rigid bodies is, in general, asymmetric if the resulting forces and moments do not sum to zero.
73 citations
TL;DR: In this paper, an analytical/numerical model which is simple in terms of modeling and efficient in computational effort is presented for the estimation of the effective stiffness properties of woven fabrics.
73 citations
TL;DR: In this article, a detailed study on the potential and limitations of performing higher-order multi-resolution topology optimization with the finite cell method is presented, where a length scale is applied on the solution using filter methods.
Abstract: This article presents a detailed study on the potential and limitations of performing higher-order multi-resolution topology optimization with the finite cell method. To circumvent stiffness overestimation in high-contrast topologies, a length-scale is applied on the solution using filter methods. The relations between stiffness overestimation, the analysis system, and the applied length-scale are examined, while a high-resolution topology is maintained. The computational cost associated with nested topology optimization is reduced significantly compared with the use of first-order finite elements. This reduction is caused by exploiting the decoupling of density and analysis mesh, and by condensing the higher-order modes out of the stiffness matrix.
72 citations
07 Sep 1994
TL;DR: Active flexible wing (AFW) technology is discussed in this paper, where two design procedures for the design and optimization of an AFW wing are described in detail, one for an existing wing and the other for a new wing using AFW technology.
Abstract: This paper discusses Active Flexible Wing (AFW) technology and describes how it differs from conventional wing design. The benefits of AFW are briefly described. Two design procedures which aid in the design and optimization of an AFW wing are described in detail. The first procedure is for the design of an AFW control system on an existing wing. This procedure optimizes control surface positions to maximize air vehicle maneuverability, without exceeding structural limits. The second procedure is for the design of a new wing using AFW technology. This procedure simultaneously couples aerodynamic, structural, and external load designs. The process optimizes a wing structure and control surface positions for minimum weight and drag, while satisfying structural constraints. = buckling constraints = bending moment = drag of case i = hinge moment = roll moment of load case i = lift of load case i = pitching moment of load case i = roll rate = torsion moment = twist and camber variables (e.g., wing jig shape design) = structural design variables = flutter constraints = structural weight = control surface positions and air vehicle flight angle design variables = roll axis inertia = roll acceleration = stress constraints of load case i {a} = vector of rigid aerodynamic panel deflections {!} = lift vector on aerodynamic panels * Project Engineer, Advanced Aircraft Member AIAA [ A ] = aerodynamic panel lift due to alpha influence coefficient matrix [ B ] = aerodynamic to structural transformation matrix [ K ] = global stiffness matrix [ d ~ / dtk] = derivative of the global structural stiffness matrix with respect to structural design variables [ S I ] =structural flexibility matrix (in units of deflection per force) on aerodynamic model [ S A ] = structural flexibility matrix (in units of rotation per force) on aerodynamic model
72 citations