Braced metallic tubes are used to dissipate kinetic energy in impact a
ttenuation devices used in transportation safety applications. Tt is a
n experimentally observed fact that these braced tubes collapse asymme
trically; even under symmetrical loading conditions. This paper examin
es the energy dissipation characteristics of such a tube when braced a
cross its diameter and subjected to lateral plate loading conditions.
Upper- and lower-bound limit analysis approaches are used to first det
ermine the initial asymmetric collapse load of the tube with diametric
al bracing oriented perpendicular to the line of action of the loads.
Then, the equivalent structure technique (EST) and finite-element prog
ram, ABAQUS, are used to determine the postcollapse characteristics of
the tube. Finally, these mathematical and numerical model predictions
are compared with experimental results to demonstrate the accuracy of
the modeling process.