In the present paper the engineering development of a structural instrument panel (IP) concept made of a Polypropylene (PP) rubber modified compound filled with 15% talc in which the metal cross car beam has been eliminated, is discussed. The design concept consists of three main injection molded shells which are vibration welded to each other to form a stiff structure. The steering column is attached to the BIW and plastic structure by means of a separate column support made of steel, aluminum, magnesium or fiber-reinforced plastic. The concept has been developed for the European market and is therefore not intended to meet the unbelted FMVSS 208 requirements. The total IP assembly has a substantially lower cost and weight than conventional cross car beam based IP structures while meeting all of the performance requirements.
The concept development was supported by static and dynamic numerical analyses using well established, widely used FEA codes.
The NVH behavior of the structural IP was studied and optimized with use of NASTRAN®. Thermal expansion was studied with ABAQUS®. The behavior during an offset deformable barrier test, head impact, side impact test and passenger airbag deployment loading has been studied with use of LS-DYNA3D®.
The optimized design showed that compared with a baseline IP structure using a cross car beam a weight saving of 2.5 kg can be achieved.