Research On Ignition Time Calibration Strategy Of Airbag In Middle And Low Speed Impact Based On Human Injury

Nowadays,the popularization of automobile airbags has reduced the occupant casualties in traffic accidents to a certain extent.However,domestic automobile manufacturers mostly use airbags from foreign suppliers,and their ignition strategies are mostly formulated according to foreign laws and regulations and the status of traffic accidents.After entering the domestic market,the product has not been recalibrated according to China’s national conditions,causing the frequent occurrence of airbag misoperations.Airbag misoperation has a threat to the safety of life and property of passengers in the car.Therefore,according to the status of domestic traffic accidents and relevant laws and regulations,and based on human injuries,this paper verifies the feasibility of the airbag calibration matrix currently used in China,and proposes amendments to address the shortcomings of existing calibration strategies.This paper mainly focuses on the existing medium-low-speed airbag calibration strategy,the main work and research contents are as follows:1.Firstly introduce the human injury mechanism,tolerance limit,and China’s frontal collision regulations and the evaluation criteria for C-NCAP frontal collision,to provide a basis for the assessment of occupant damage later.2.This paper establishes the finite element model of 100% positive rigid wall collision under 56 km/h speed of Toyota Yaris,and establishes the model of occupant MADYMO constraint system of the cockpit of this model,and verifies the reliability and accuracy of the model according to the test data.The results show that the model is reliable and accurate,and can be used in the next research work.3.For the validity of the widely used airbag calibration matrix,a finite element model and a occupant constraint system model under 25 km/h speed collisions are established.By comparing the damage value of the airbag to the driver under different ignition states,it is determined that Make sure the airbag should not be deployed at a speed of 25km/h.Because the commonly used calibration airbag matrix has certain limitations and is not suitable for this vehicle,it should be adjusted.4.For exploring the reasonable airbag calibration matrix and determining the speed threshold of airbag’s ignition,this paper compares the damage value caused by different ignition states of the air bag to the driver under several vehicle speeds,and determines that the vehicle’s speed threshold of airbag’s ignition should be 35km/h,and the protective effect of the airbag on the head is obvious.Reasonable vehicle’s speed threshold can effectively reduce the occurrence of airbag misuse in low-and-medium-speed collisions,and improve vehicle safety and economic maintenance.5.In order to further improve the airbag calibration matrix,the simulation of different collision speed and different airbag ignition time is carried out for this vehicle.Through the detailed comparison of the injury and analysis of the change trend of the injury,it is found that the optimal ignition time of the airbag is 28 ms after the collision at 40km/h,while 26 ms after the collision at 40km/h.In 45km/h collision,the best ignition time of airbag is 24 ms after collision.