Comparison of the energy absorption by tapering of tubes with other forming processes.

A major concern of the automotive industry is to reduce the weight of cars. At the same time security of the passengers has to be improved. One possibility to reach these aims is to use materials like fibre reinforced composites or magnesium alloys. Another possibility is to use conventional materials in connection with a controlled deformation process. This paper discusses the tapering process of steel or aluminium tubes in dies. Extensive experimental programs performed at the Institute of Mechanics in Hannover revealed that the tapering process is more efficient than tube inversion or progressive buckling of circular tubes. Therefore it has a great potential in the automotive industry. The mechanics of the tapering process is described by using kinematic relations and energy considerations. The closed-form solution presented in this paper shows a good correlation with experimental data. For the covering abstract see ITRD E116488.