Abstract
Pedestrian protection is one of the main research fields inside the automotive safety and one of the main pillars of innovation in the automotive industry. Data accident shows that each year died 6000 people in Europe as a consequence of a traffic accident.
The lower extremities are represented by the lower legform impactor in the laboratory tests. The lower legform that is being used nowadays is the one of the TRL. The magnitudes that it measures and the biomechanics limits are:
- Acceleration; with 150 g as a limit value.
- Knee bending angle; angle between tibia and femur, with 15º as a limit value.
- Shear displacement; gap between tibia and femur, with +/- 6 mm as a limit value.
The main target of this research project is to obtain a simplified model to analyse and to predict the behaviour of the front of the vehicle in the lower legform pedestrian protection.
The parametric model has been done thinking into account 2 main aspects:
- The possibility to maintain the contact points between the front of the vehicle and the lower legform impactor, basic to determine the dynamics of the impactor.
- The possibility to change the geometric configuration of the parts of the front of the vehicle, to see how the influence is when introducing changes in the original configuration.
First results show that this simplified model correlates with the original one; so this simplified model can be used to predict the results of the vehicle in pedestrian protection. In this research project, the variables which have been analyzed are mainly:
- The longitudinal gap between the main crossbeam and the pedestrian crossbeam.
- The vertical gap between the main crossbeam and the pedestrian crossbeam.
- The longitudinal gap between the main crossbeam and the skin of the front.
- The vertical position of the whole front compared to the legform.
- The speed of the impact.
- The material of the non-metallic components of the front.
The results found in the creation of this model with the relations of the geometric variables of the front of the car indicate that there is a relation between the increasing of the high of the car and the increasing acceleration and knee bending in the lower legform impactor and when there is a decreasing high of the front there is an increasing shear displacement in the lower legform impactor. Moreover, when the longitudinal gap between the main crossbeam and the pedestrian crossbeam increases in a positive way, the knee bending and the acceleration increase and when the gap increases in a negative way, the shear displacement increases.
Keywords: Lower legform, pedestrian protection, simulation tools, simplified model