Advanced Frontal Crash Finite Element Dummy Development And Damage Research

In order to develop a safer occupant protection system,researchers generally evaluate the passive safety performance of the car by collision test.In the collision test,the vehicle crash dummy is used as a substitute for the human body,using its"bionics"to evaluate the safety performance of a car.As an important tool and part of automobile crash test,the dummy plays an irreplaceable role in the development of automobile safety performance.With the continuous development of computer,numerical simulation technology has been widely applied in the field of vehicle crash safety research.In the process of vehicle development,the finite element simulation method can greatly reduce the cost of vehicle development and shorten the development cycle.In China,the research of vehicle passive safety and crash dummy start late,There is still no internationally recognized crash dummy or dummy producer in domestic,and the finite element dummies used in the study are all dependent on import,the high cost is paid every year.The automobile industry generally adopts the dummy in Europe and America as a testing tool.Our vehicle safety regulations and standards are also based on the European a nd American dummy,which can't well simulate the damage of the most widely crowds in China in the accidents.This paper aims to develop an improved front crash finite element dummy,which can reduce the calculation time and improve the efficiency of calculation while the accuracy of the model is guaranteed to reduce the cost of automobile development.And on this basis,we develop a model of crash dummy in accordance with the size of Chinese human body to study the differences in damage of the body of different sizes in the frontal crash.By studying the damage mechanism of the occupant in vehicle collision and the structure of the Hybrid III 50^th frontal crash dummy,establishing the finite element dummy model and optimizing the structure of the model.In order to improve the accuracy of the finite element dummy model,this paper proposes a multi-objective optimization method to optimize the parameters.In order to obtain the characteristic curve that can reflect the mechanical response of each part of the dummy,the Hybrid III 50^th dummy is calibrated.The response surface method based on the central composite test design is used to construct the two polynomial agent model of the optimal target with the response curve as the target,and use genetic algorithm to optimize the model to make the model's response more truly.In order to verify the validity and accuracy of the optimized dummy finite element model,the model is verified under calibration and vehicle frontal crash test condition.A finite element model of two domestic vehicles is built.The improved finite element dummy established in this paper is used to carry out frontal 100%overlapped rigid barrier impact test and 40%overlapping and deformable wall impact test,and the results are compared to the real vehicle crash test.The results show that the finite element dummy developed in this paper can better reproduce the test results,and has higher mechanical performance simulation quality,less calculation time,which can be applied to the study of vehicle frontal crash.To study the damage difference of human body with different sizes in vehicle collision.Based on the improved finite element dummy developed in this paper,the dummy in accordance with the size of Chinese human body of is established by using the scaled method.The result shows that occupant restraint system based on the European and American body size can't well protect the Chinese dummy,so it's necessary to design car safety for the market of our country.