Adaptive Crashworthiness of Front-End Structure of Motor Vehicles

The aim of this research is to present a new concept of adaptive crashworthiness system. Main objectives of the proposed system are to predict, control and adjust the impact characteristics to various conditions by decreasing the pre-designed crushing stiffness of the vehicle frontal deformation zone. According to the initial pre-crash parameters (velocity, mass, stiffness and overlap) the prospective system can select proper crushing force. In most basic approach each absorber has two levels of the crushing stiffness - high and low. De-stiffening feature is driven by pyrotechnic detachable connectors integrated in the frontal car structure, which can be destroyed causing disconnection of selected structural members, excluding them from the energy dissipation process. Pyrotechnical stiffness control can be activated in a very short time, sufficient to act during typical road accidents. Among other things, the presented idea can be used to solve mass compatibility problems. Results presented in this paper show that adaptive frontal structure can help in crash performance optimization, by adjusting system properties to the various conditions of impact scenario. Decrease of the front-end crash stiffness of a striking vehicle and extension of the crushing distance can decrease occupant risk through limited side intrusion and improved deceleration pulse shape, comparing to passive systems. Detailed procedures of the crash structural control are shown. Results of simulations performed in explicit finite element code and the experimental results are demonstrated. Sensing technology is not discussed.