A Study Of Passenger Injury And Protection In A Coach Frontal Impact

Coach crash accident is the main reason that results in catastrophe traffic accidents in China.According to surveys,the injury of passenger in a coach accident is strongly correlated to the secondary collision.There is no existing mandatory regulation for a full coach frontal impact in the worldwide,although the national standard of GB13057-2014 that emphasizes the strength of the seats and their anchorages of passenger vehicles,to some extent,has promoted the development of safety design of vehicle seat in china,the problem of occupant safety in coach frontal impact has not been thoroughly solved due to the various interiors and different seat layout;in addition,the seatbelt using is not compulsory.This study will focus on the safety characteristics of the passengers with different locations including the first row and non-first row.The aim of the first part is to investigate the effects of passenger seatbelt and seat layout on the behavior of passengers with non-first row seats.The sled tests were conducted based on the regulation GB13057-2014 and the effect of the seatbelt on the kinematic of passenger was assessed.A numerical model of seat-dummy was established using coupling method of finite element and multi-body and validated against the sled tests.Virtual testing were subsequently carried out under different scenarios of6 sets of seat pitch,5 sets of height difference and 5 sets of seat back angles respectively using single factor variable method to evaluate the effect of seat layout on the occupant kinematics and head HIC,neck Nij,chest 3ms combined acceleration,femur axial force and tibia index TI.The results show that without a seatbelt,the passenger can be easily ejected resulting in serious out-of-position;however the passenger was restrained through the abdomen with a 2-point seatbelt remains in the seat with its head and lower limb collided with the front seat.In addition,the axial force of the femur reduces as the seat pitch increases;the the neck Nij,the femur force and the tibial index of the lower leg rises as the high the front seat increases;the peak acceleration of the head and the neck injury value Nij increases,but the femur force reduces as the enlargement the seat back angle enlarge.The aim of second part is to study the safety characteristics of the first row passenger in the coach frontal impact.A local numerical model of the bulkhead-dummy model was established and validated against the fixed barrier frontal impact test.The safety of the passenger seat behind the bulkhead was studied under different scenarios of 4 sets of bulkhead-seat spacing in a coach frontal impact.The differences of kinematics and injury of passengers restrained with 3-point seatbelt,2-point seatbelt and without seatbelt were evaluated.The results show that with 2-point seat belt,the injury of head increase but the tibia index decrease as the bulkhead-seat spacing varies from 280 mmto 400mm.Two-point seat belt can only restrain the lower limbs of the passenger.Comparing with two-point belts,three-point seat belts can effectively restrain upper body movement of the passenger and protect the its head.The results of this paper can provide the basis for the safety protection strategy of the passenger in different positions of the bus,and provide a favorable reference for the interior layout and interior design optimization.