Simulation And Optimization Of Front Passenger Restraint System Based On MPDB Collision Condition

Frontal collisions are the most common and most common form of collisions in traffic accidents.In order to ensure the safety performance of automobiles and reduce the casualty rate of accidents,automobile powers have formulated corresponding automobile safety test regulations,such as FMVSS208 regulations in the United States,E-NCAP in Europe and C-NCAP in China(2006).Over the past ten years since the implementation of C-NACP,the overall safety technology level of my country’s automobiles has been effectively improved,and the C-NCAP version has also been supplemented and improved many times.In the 2021 version of C-NCAP,a new frontal impact test MPDB(Mobile Progressive Deformation Barrier Impact Test)has been added to the occupant protection test,and replaced the 64 ODB frontal offset crash that has been used until now.Compared with the 64 ODB crash test condition,the MPDB crash test condition is a vehicle-vehicle collisiodn.Both the test vehicle and the barrier car collide with a 50% offset at a speed of 50km/h;at the same time,the MPDB crash test adopts biological simulation.The higher and more expensive THOR dummy can more accurately simulate the injury of the occupant in the event of a collision.Therefore,the research on the occupant damage mechanism under MPDB crash test conditions is of great significance to further improve the level of vehicle safety technology.Based on the MPDB crash test procedure in the 2021 version of C-NCAP,this paper establishes a simulation model of the occupant restraint system under the MPDB crash condition to explore the damage mechanism and damage situation of the dummy under this condition.Finally,the ISIGHT optimization software is used to optimize the restraint system.System parameters are optimized.The main research contents are as follows:(1)According to the FFB data of the company’s frontal 100% crash test,the simulation model of the restraint system under the 50 FFB crash condition was established,and the validity of the restraint system model was verified by benchmarking with the test data;then the finite element model of the MPDB crash test was established The simulation model is used to obtain the acceleration of the MPDB crash test,and the acceleration value and the THOR dummy are replaced with the established FFB restraint system simulation model,thereby obtaining the MPDB restraint system simulation model.(2)Through the comparative analysis of the damage of the dummy under the FFB collision condition and the MPDB collision condition,it is concluded that under the MPDB collision condition,the chest compression of the THOR dummy is 57 mm,which is close to the chest damage specified by C-NCAP.The low level index is60 mm,so the restraint system must be optimized to reduce the chest injury of the THOR dummy.(3)Using ISIGHT software to optimize the parameters of the constraint system.First,the Latin hypercube method was used to conduct the DOE test design and sensitivity analysis,and the parameters of the restraint system that had a greater impact on the chest of the THOR dummy were selected.Finally,taking the minimum chest compression amount of the THOR dummy as the optimization goal,an approximate model is constructed,and an appropriate optimization algorithm is selected to submit the calculation.The final result is that the chest compression amount is only reduced by about 3mm,and the optimization effect is not very satisfactory.(4)In order to reduce the chest compression of the THOR dummy and improve the chest injury of the dummy,three seat belt optimization schemes are proposed,namely constant force limit CLL + end piece preload,increasing force limit PLL +end piece preload and decreasing limit Force DLL + end piece preload.The simulation results show that the use of decreasing force-limiting seat belts and endpiece preload can effectively reduce the chest compression of the THOR dummy.The chest compression of the dummy is reduced from 57 mm to 43 mm,the dummy chest score increased from 0.48 to 2.72,which effectively improves the chest of the THOR dummy harm.