Bumper model improves testing

Opel and BASF have used a new mathematical model to create a plastic car part which will reduce the risk of injury during collision with a pedestrian.

The lower bumper stiffener (LBS) is made of BASF’s Ultramid B3WG6 CR, a reinforced polyamide 6 developed for crash applications. The LBS weighs about one kilogram, is one metre long and is installed behind the front bumper so as to reduce the risk of serious knee injury in the event of a collision with a pedestrian.

BASF used a new method of integrative simulation to develop LBS. The numerical material model takes into consideration the directionally dependent behaviour of glass fibre-reinforced thermoplastics. Along with the material parameters of the pure plastic, the content, geometry and orientation and distribution density of the fibres in the finished part all form part of the calculation.

The simulation is fed with the findings from a classic mould-fill simulation and the experimental data obtained from a high-speed measuring device made by BASF. This gives the part shape that best complies with the requirements as well as the optimum mould design.