Untersuchung zur Verbesserung des Crashverhaltens eines 2-Kammer-Profils

The Master's thesis at hand is dealing with the improvement of the crash behaviour of an existing two-chamber column. The high-strength aluminum alloy used for the production of this extrusion pro le has a low ductility. Thus, during axial crushing crack formation occurs due to large plastic deformations. The objective of the present thesis is the minimisation of this crack formation as a consequence of increased energy absorption by means of special geometric modi cations of the column T-shapes. The simulation of the crushing has been conducted with the software LS-DYNA using an elastic-plastic material modeling and a damage model for ductile failure prediction. For the setup of the simulation model a mesh study and an investigation of the e ects of mass scaling have been carried out. The geometric modi cation of the column T-shapes is based on a method for notch shape optimization, called method of tensile triangles according to Mattheck, which is being applied on the radii of the T-shapes of the pro le. During wrinkle formation the occurring stress peaks in the rst fold of the column are being analyzed and the original geometry is being compared with the altered geometry. It is shown that the geometry modi cation does cause a stress reduction in the T-shapes. The comparison of the simulated crash behaviour of the two types of columns shows that less failure occurs and the energy absorption is increased. In a parametric study the in uence of di erent sizes of the new geometry on the crash behaviour is being investigated with the aim of nding the optimum. In order to validate the simulation results experiments have been carried out, which do con rm the outcome of the simulation. As a conclusion additional elds of application of the new geometry on columns and possible approaches for further improvement of the two-chamber column as well as the simulation model are being proposed. vi