Inclusion of lower leg injury criteria in the new European Frontal Impact Legislation has meant that lower leg loads for front seat occupants and footwell deformation have to be considered as part of the vehicle design process at the concept stage.

The Hybrid III dummy with instrumented lower legs is the tool selected for measuring the lower leg injury criteria and it is essential to have a full understanding of the lower leg interaction, with the deforming footwell, control pedals and dashboard, in order to determine how these effect leg kinematics and loading mechanisms.

The LLIMP (Lower Leg Injury and Methods of Prevention) Vehicle Design project is a collaborative research project undertaken by MIRA and sponsored by Rover Group, Ford Motor Company and Jaguar Cars. Its aim is to gain an understanding of the effect which car design has on lower leg kinematics and loading mechanisms. As part of this project a finite element lower leg model has been developed and fully correlated to crash and sled tests. The effect of over 30 different parameters which affect lower leg kinematics and loads have been studied, and their effect on lower leg loading will be evaluated later in the project using the finite element lower leg model. These parameters take account of vehicle structure, occupant kinematics and footwell geometry. The results of the parametric study have been collated to produce a set of lower leg design guidelines, to assist in vehicle structure and restraint system design and as part of the vehicle development cycle.

The paper presents the formulation of the parameters, and how different parameters effect lower leg kinematics and injury criteria.