Worldwide involvement in Global Technical Regulation (GTR) discussion shows the
increasing importance of pedestrian safety as a global concern. Vehicle front
styling plays an important role in vehicle to pedestrian impact. Front styling
can change the pedestrian kinematics and injury levels during an impact. Key
elements of bumper front are Fascia, Upper & Lower Grille, Hood, spoiler or
undertray, bumper beam and height of these components from ground level,
determine the vehicle aggressiveness for pedestrian safety.
This paper presents an approach to diagnose the vehicle front aggressiveness for
pedestrian leg impact. Eight different vehicle bumper front configurations from
‘minis’ to ‘sedans’ are studied for lower leg impact cases, to understand the
bumper stiffness profile (stiffness in upper, middle and lower load path).
Numerical models are derived to relate the knee deceleration; knee bending and
tibia shear with bumper stiffness profile, through extensive Computer Aided
Engineering (CAE) and Design of Experiments (DOE) based numerical studies. The
desirable ‘vehicle front stiffness profiles’ are identified for development of
efficient pedestrian countermeasures and different front-end energy management
solutions are proposed to achieve the same, using thermoplastic materials,
commonly used material to design energy absorbers for pedestrian safety.