Crashworthiness study of a keel beam structure

In this paper, crashworthiness of the energy-absorbing keel beam that could be used for sub-floor of an aircraft was numerically studied using finite element software (ABAQUS/EXPLICIT). Effects of various parameters, i.e. web thickness, radius of everting stringer, and friction coefficient, were investigated and the conditions under which the keel beam could produce progressively crushing deformation were explored. The results show that web thickness, t, and radius of everting stringer, r, have great influence on the performance of the keel beam. When the ratio of r/t is in the range of 4–6, a low peak force (peak force reduction of 50%), stable and relative high stress plateau, and progressively crushing deformation mode can be produced from the energy-absorbing keel beam. By selecting appropriates parameters, energy absorption behavior has been significantly improved comparing with the traditional keel beam. Finally, a new energy-absorbing keel beam with variable web thickness was proposed. It has been demonstrated that the keel beam with variable web thickness is an ideal crashworthiness structure. It could not only significantly reduce the peak force, but also remain the stable and effective force plateau; meanwhile avoid web buckling.