INFLUENCE OF LIPS ON THIN-WALLED SECTIONS

Turning the free edge of an unstiffened flange inwards or outwards to form a 'lip', can substantially improve the local buckling resistance of a member. The lip is the most common type of edge stiffener used in cold-rolled, thin-walled sections. In this paper the behaviour of pla te elements of thin-walled sections stiffened by compound lips (i.e. l ips which are folded twice to form 'lips on the lips) is examined both theoretically and experimentally. An outline of a series of tests on compound edge-stiffened thin-walled sections of various geometries is given and some load-end compression displacement paths are compared wi th the theoretical predictions. Reasonably good agreement is obtained between the experimental and theoretical results. Comparisons of the t heoretical predictions with experimental results of other researchers are also presented in this paper.