Speaker
Description
The stringer sheet forming process chain enables the cost-effective production of components with significantly increased stiffness for mass markets such as the automotive sector. In the first process step, a stringer is added to a conventional sheet by laser welding. In the subsequent process step, the stringer sheet parts are formed by a deep drawing operation. Previous investigations of component performance focused in particular on the static stiffness of the stringer sheets. The behavior under dynamic load, such as in crash events, has not been systematically investigated to date. This study characterizes the crash performance of stringer sheet components by means of a drop hammer test. First, the boundary conditions for the experiment are determined via numerical simulations. The energy absorption of the components is evaluated in the experiment based on the rebound height of the drop hammer, whereas the structural integrity is characterized based on the maximum dynamic as well as permanent deformation. The components are varied fully factorially with respect to the parameters stringer height, stringer thickness, thickness in the base sheet and the height profile of the stringer. In addition, spot sample tests are carried out for additional parameters mainly derived from the forming process, for example blank holder force, lubrication, and presence of a draw bead. The influence of these parameters on the energy absorption and structural integrity is assessed. Noticeable discrepancies concerning the influence of the parameters on the static behavior of the components are discussed in detail. Furthermore, the results of the numerical simulations are validated against the experimental results.