Development of a lightweight instrument-panel support structure - Material and production concept of the instrument-panel support tube made of long-glass-fiber-reinforced partly aromatic polyamide for the BMW M4 GTS

摘要

The support structure was originally designed as the carrier for the cockpit integration module and in this main function also contributes to the structural rigidity of the body in the bulkhead area. Mounted on it are instrument panel, glove boxes, airbags, steering column, EE components, and so on. The component must exhibit a high degree of rigidity over the full temperature range in the passenger compartment and in both vehicle operation and crash situations is subjected to high static and dynamic forces. Load-bearing structures normally take the form of welded metal constructions (steel, aluminum) or magnesium die castings. As part of a preliminary development project a support structure made of long-glass-fiber-reinforced thermoplastic was developed which has been developed and industrialized up to readiness for series production for the M4 GTS special series. The use of a long-glass-fiber-reinforced thermoplastic material meant that a weight saving of approx. 1.6 kg could be saved in comparison with the series component made of steel. This paper examines not only the component requirements and material selection based on this, supported by mechanical and rheological calculations, but also production aspects.