Browsing by Author "Yang, RT"

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A consistent finite element formulation for linear buckling analysis of spatial beams
(1998-04-14)
Hsiao, KM
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Yang, RT
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Lin, WY
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機械工程學系
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Department of Mechanical Engineering
A consistent co-rotational finite element formulation and numerical procedure for the linear buckling analysis of three-dimensional elastic Euler beam is presented. A mechanism for generating configuration dependent conservative moment is proposed and the corresponding load stiffness matrix is derived. It is assumed that the prebuckling displacements and rotations of the structure and the corresponding deformations of the elements are linearly proportional to the external loading. The prebuckling rotations of the structure are fixed axis rotations or small rotations, and the effect of the prebuckling displacement on transformation matrix for the coordinates transformation can be ignored. All coupling among bending, twisting and stretching deformations for beam element is considered by consistent linearization of the fully geometrically nonlinear beam theory. An inverse power method for the solution of the generalized eigenvalue problem is used to find the buckling load and buckling mode. Numerical examples are presented to demonstrate the accuracy and efficiency of the proposed method. (C) 1998 Elsevier Science S.A.
Effect of member initial curvature on a flexible mechanism response
(1996-02-22)
Hsiao, KM
;
Yang, RT
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
A co-rotational finite element formulation of slender curved beam element is presented to investigate the effect of member initial curvature on the dynamic behaviour of planar flexible mechanisms. The Euler-Bernoulli hypothesis and the initial curvature are properly considered for the kinematics of curved beam. The nodal co-ordinates, incremental displacements and rotations, velocities, accelerations and the equations of motion of the system are defined in terms of a fixed global co-ordinate system, while the total strains in the beam element are measured in element co-ordinates which are constructed at the current configuration of the beam element. The element equations are constructed first in the element co-ordinate system and then transformed to the global co-ordinate system by using standard procedures. Both the deformation nodal forces and the inertia nodal forces of the beam element are systematically derived by consistent linearization of the non-linear beam theory in the element co-ordinates. An incremental-iterative method based on the Newmark direct integration method and the Newton-Raphson method is employed here for the solution of the non-linear dynamic equilibrium equations. Numerical examples are presented to demonstrate the effectiveness of the proposed element and to investigate the effect of the initial curvature on the dynamic response of the flexible mechanisms. (C) 1996 Academic Press Limited