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From:
T. Ohtsuka (1) and S. Motoyui (2)
(1) Department of Mechanical Systems Engineering
(2) Department of Built Environment
Tokyo Institute of Technology, Yokohama, Japan,
"Analytical method for elastoplastic buckling behavior of H-section truss elements involving local buckling", doi: 10.4203/ccp.75.26, Paper No. 26 in Proceedings of the Sixth International Conference on Computational Structures Technology edited by B.H.V. Topping and Z. Bittnar, 2002
SUMMARY: The post-buckling benaviour of slender member like a chord of truss structures generally implies extremely strength degradation. So the peculiar n-u curve given from experimental results and so on is usually used as the axial force-stretch relation of members when we analyze such truss structures. At this case, however the theoretical background and validity in its treatment are not clear in view of thermodynamics.
Even if the member's slenderness ratio is the less, the member is composed of H section and so on, its strength degradation benaviour become much more extremely because of local buckling. In order to evaluate the influence of local buckling, we usually use the finite element method with discrete model, but it is very costly to evaluate the local buckling by using the discrete model because the model requre many elements to acheve a accurate result.
So far, to analyze the elastoplastic local buckling benaviour, the simplified method like the simple plastic hinge model, multi spring model were proposed. But similary above mentioned method using the peculiar [n versus u] curve, the theoritical background of these model are not clear and its application to the member subjected to high axial force is inappropriate. On the other hand, for the high axial loading member, we use the generalized plastic hinge model. But this model is not applied to local buckling benaviour.
In previous papers, we proposed a method [1] based on the thermodynamics to analyze the post buckling benaviour of elastoplastic compression member, and from investigation into the buckling benaviour of truss beam [2], we suggested a beam element [3] involving local buckling by regarding the effect of the local buckling as the softening in resultant stress space, (M,N) .
Then in this paper, we will extend the foreging method and propose a new consistent convenient analytical method to evaluate the post buckling benaviour involving local buckling for H-section slender member....
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