The Virtual Test Research On Airbag Protection Efficiency In Vehicle Frontal Crash

Vehicle traffic accidents lead to large number of death and social economy losses every year in the world. Both active and passive safety problems attract more and more attention in each country. It is well known that airbag restraint system is an effective passive safety equipment, In industrialized countries such as the European countries and the USA it is required that airbag is to be equipped in passenger cars. In recent years, the new cars are almost equipped with airbags in China. However, traffic injury epidemiology indicates that airbags provide the protection to the passengers, and it also have injury risk to the passengers when they are out of normal sitting position. As far as the airbag restraint system design is concerned, it is the key problem to make good use of airbag while to eliminate the side effects in the mean time. So, the airbag design and matching with passenger cars is carried out in the frontal crash condition. The influence of airbag fold pattern on the out of position passengers is investigated, and the influence of airbag deployment on the head-neck injury is also studied in this dissertation.The methods and fundamental theory in study of airbag protection techniques in the vehicle frontal crashes are described. The airbag protective efficiency in combination with the seat belt is analyzed by using the finite element airbag models of the driver side and passenger side in multi-body model of a passenger car compartment. The models are implemented by using both MADYMO and DYNA programs. The passenger injury parameters are analyzed in terms of the main airbag parameters, such as the airbag volume, vent hole size, inflator mass flow rate and triggering time. An optimization of the airbag model is carried out using MADYMIZER, and the optimization results are validated against the test results.The dynamic process and pressure of the airbag deployment is analyzed by using the Petri-fold method. A program with the Initial Matrix Method (IMM) is developed to automatically establish a reference mesh model and a mapping mesh model. The parametric design is made for the airbag diameter, folding times, folding ring distance and folding density, and then development process of the model and the mapping algorithm are implemented and evaluated through a case study. Airbag models are developed using three fold patterns: leporello-fold, spiral-fold and petri-fold. The virtual testing of airbag static deployment, dynamic deployment against impactor, and...