Computational & Technology Resources
an online resource for computational,
engineering & technology publications
INNOVATION IN COMPUTER METHODS FOR CIVIL AND STRUCTURAL ENGINEERING
Edited by: B.H.V. Topping and M.B. Leeming
Post-Buckling of Portal Frames - Reduced Number of DOF Models
P. Providencia and E. Costa
Department of Civil Engineering, University of Coimbra, Coimbra, Portugal
P. Providencia, E. Costa, "Post-Buckling of Portal Frames - Reduced Number of DOF Models", in B.H.V. Topping, M.B. Leeming, (Editors), "Innovation in Computer Methods for Civil and Structural Engineering", Civil-Comp Press, Edinburgh, UK, pp 59-64, 1997. doi:10.4203/ccp.50.4.2
The present article exposes the incipient post-buckling behaviour of discrete elastic portal frames with a minimum number of degrees of freedom. It demonstrates that these simple models are sufficient to describe a qualitative behaviour which although generally known is also frequently forgotten or neglected because the continuous problem analysis is quite complex. In particular, the sign of the incipient curvature of the symmetric bifurcation path associated with the sway mode is shown to depend on the ratio between the beam and columns lengths (whose inverse represents a ratio between the corresponding bending stiffnesses). On the other hand, the nonsway mode appears from an asymmetric point of bifurcation.
The substitution of rigid connections by semi-rigid is also shown not to produce any drastic change to the qualitative behaviour in the post-buckling range.
purchase the full-text of this paper (price £20)