A large-deflection design technique for the collapse and roll-over analysis of thin-walled tubular frames

摘要

A large-deflection design technique is presented for the thin-walled tubular frames which form the superstructure and roll-over protection of passenger buses and other such vehicles. The load-displacement behaviour of a collapsing two-dimensional frame was modelled to large deflections by combining separate elastic and rigid-plastic analyses. Accurate modelling required accurate predictions of the frame's deformed geometry and insertion of the large-rotation moment-rotation properties of thin-walled tubes into the rigid-plastic analysis. A unique pure bending rig was used to measure the moment-rotation properties and elastic step-by-step analysis was used to model the behaviour of the frame up to the point at which the frame formed a kinematic mechanism.