Study On Occupant Protection Performance Affected By The Combination Of Autonomous Emergency Braking And Reversible Pretension Seatbelt

With the increasing requirement of automobile safety, and the continuous development of active safety and passive safety technology, the concept of "Pre-crash" is produced. Autonomous emergency braking system(AEB) and reversible pretension seatbelt are considered to be the two important content of Pre-crash safety system. Although AEB can avoid collision or decrease collision intensity, but it would also lead to occupant leaning forward away from the right position, once a collision occurs, it might reduce the protection effectiveness of restraint system, increase the occupant injury risk, especially when the initial sitting position of the occupant is out of position. The reversible pretension seatbelt can provide an anti-directional force control and restraint occupant in Pre-crash phase, the combination of the two can provid e more effective protection. However, at present, there are few studies on the protective effect of the AEB and reversible pretension seatbelt in different sitting postures, especially under the action of AEB, the research on the parameter matching among reversible pretension seatbelt and pyrotechnical pretension seatbelt and airbag are very scarce.Based on this, this paper uses computer simulation method to study the effect of the combination of AEB and reversible pretension seatbelt on the normal and out-ofposition occupant protection as well as the parameter optimization of the constraint system. The main work and research contents of this paper are as follows:1. A frontal crash simulation model of driver side occupant restraint system with AEB and reversible pretension seatbelt was established, and application of active human body model. On the basis of normal sitting position, the other four out-of-position occupant restraint system simulation model was established.2. For five sitting position occupant, there are three kinds of situations, no AEB no reversible pretension seatbelt, with AEB no reversible pretension seatbelt, and with AEB and reversible pretension seatbelt, and compared with the displacement and injury of occupant of the three situations.3. Take the normal position occupant as the object, a comprehensive method involving design of experiments(DOE), Kriging model, and Multi-Object Genetic Algorithm II(MOGA II) is conducted to perform a multi-object optimization, and Weighted Injury Criterion(WIC) is used to determine the optimum solution. Finally, the impact strength is increased to 64km/h to verify the robustness of the optimal solution.4.By using the Pareto optimal solution set of the five sitting postures, the optimal configuration of the occupant restraint system in different sitting postures is obtained and its characteristics are analyzed. And analyzes the occupant injury under the optimal configuration of different sitting posture restraint system.Paper research shows that: Only under the action of AEB, after the collision, it will increase the forward displacement of occupant, especially when the initial sitting position is out of position, which leads to the increase of the local damage, especially the thoracic injury. Under combination of AEB and reversible pretension seatbelt, the forward displacement was improved caused by the AEB, for OOP02 and OOP03, it can also play a role in correcting the initial position, and occupant damage and risk of injury are significantly reduced. The more serious the initial out-of-position, the more obvious the risk of injury reduction. After the multi-objective optimization of normal and out-of-position occupant restraint system, the more serious the initial out-ofposition, the more obvious the optimization effect. From IP to OOP04,the drop of WIC were 6.73%、10.59%、21.58%、10.70%、20.33% respectively. The optimal parameters matching among reversible pretension seatbelt and pyrotechnical pretension seatbelt and airbag in different initial sitting position is obtained, to provide guidance for the application of the reversible pretension seatbelt and the design of adaptive occupant restraint system.