MAKING INTEGRATED OCCUPANT SAFETY SYSTEMS ASSESSABLE - VIRTUAL ASSESSMENT APPROACH FOR VARIABLE SEATING POSITIONS AND PRE-CRASH CONDITIONS

Due to legislative regulations, consumer tests and the ongoing improvements including new relevant test proposals for different scenarios, state of the art occupant restraint systems are continuously increasing the safety level in the field of operation. However, today's test procedures for vehicle safety systems take into account only one standardized occupant position for each scenario and do not consider any relative movement of the occupant or different seat positions prior to the impact. This is a reasonable boundary for the comparability of vehicle safety ratings. Considering a wider range of human-like occupant conditions at in-crash t0 there is no established method available, but subject to lively research activities. Especially the pre-crash phase of real life crash scenarios is varying due to e.g. environmental conditions (e.g. road friction), vehicle specifications (e.g. Automatic Emergency Braking) and different occupant postures and reactions. Taking into account advances in integrated safety systems and the introduction of new adaptive restraint systems a high potential for the improvement of safety of all possible relevant occupant positions is obvious. Development of basic knowledge for the understanding of combined effects is addressed within current research activities, with the use of dummies, human body models and volunteer tests. A wide variety of sensing principles and algorithms (logic) as well as their combinations amongst others are used for the realization of Individual Occupant Protection (IOP) functions. This paper describes a virtual simulation method using dummies to assess the IOP potential for combined pre-/in-crash scenarios focusing on occupants deviating from the “standard” position and to derive characteristic parameter for IOP functions. This input is needed to answer this paper´s central research question, on how a reliable and adequate risk assessment for a specific not standard initial occupant position due to defined pre-crash actions can be realized. As an example, a variety of pre-crash scenarios including forward and rearward moved seat positions for the passenger as well as the methodology to generate these scenarios are assessed. Thereby different initial conditions for forward displaced dummies through an accelerated pre-crash phase and a following crash pulse are simulated. One benefit is the severity evaluation of a high quantity of simulations within one simulation environment including the kinetics of the pre-crash phase. The elaborated method is based on a well-validated generic state of the art occupant sled model and two dummies (Hybrid 3 50 % and 5 %) for LS-Dyna. The selection of the Hybrid 3 version additionally enables the possibility to compare it with real tests results. The results emphasize the need for personalized restraint optimization strategies for the out-of-standard position occupant. Characteristic parameters of future interior sensing sensitivities for the pre-crash phase are superimposed by the in-crash risk assessment.