The optimisation of the performance criteria for the head impact of a next generation instrument panel is discussed. The applied process allows the manufacture of laminated systems, which incorporate structural, and energy absorbing expanded polypropylene foam elements. An integrated padding in expanded polypropylene provides the structural base element where functional parts can be attached and offers an excellent absorption medium.
The tailoring of the actual instrument panel was made possible through the development of the finite element material model reflecting the dynamic material characteristics of the thermoplastic foam. The influence of impact velocity, shape, foam density and bottoming-out of the energy absorber are discussed.
An excellent agreement with experimental results makes the thermoplastic foam material model an effective engineering tool allowing automotive development engineers to simulate expanded polypropylene foam in occupant safety and dynamic impact applications.