Restraint System Analysis And Design For A Car Basic On Occupant Energy Management

1.PrefaceAutomobile safety has attract more and more attention day by day.The developed countries have established mandatory rules to protect the occupant.The pursuit of security of automobile enterprises is to meet the conditions for a higher evaluation of the new evaluation procedures NCAP(New Car Assessment Program).Because the purpose of NCAP is to tell consumers which car is more safety and the safety of the car directly linked with the market, which makes automotive safety has become the topic of concern.Therefore analysis of motor vehicle safety and improve the safety of motor vehicles throughout the automotive design and product process is extremely important.NCAP greatly promote the implementation of the automobile manufacturers in the automotive safety technology innovation.In recent years,the introduction of China new evaluation system(CNCAP) make Chinese consumer understand automobile safety deeper and deeper.This led major car manufacturers speed up their development of automobile safety technology in order to get higher test score levels in CNCAP.Automobile safety analysis is a theory with clear physical meaning base on the summary of automobile collisions experimental data,in order to guide the design direction of vehicle frontal impact.This theory's ultimate purpose is to protect the crew during the impact.When vehicle collision occurred,the structure deformation of the body absorbs impact energy first of all,and its aim is to provide a stable acceleration environment to the occupant. In a very short period of time,the occupant will interact with the restraint system.Good match with the body of the restraint system can not only effectively prevent the secondary damage caused by the collision,but also effectively slowed down the deceleration.Based on energy analysis,a clearer understanding of the occupant total energy consumption in the collision process is received,and the information of restraint system optimization is provided from the energy management perspective.The restraint system is of the one of the main study in the field of automobile passive safety.The study is focused on the mechanical properties of the subsystems,such as seat belts and airbags,and its aim is to obtain the optimal performance,so that makes the human body avoid the second collision with the cabin interior components;the development of safety seats,energy absorbing steering,security panels,interior trim components with energy absorption cushioning material reduce the human body to minimum harm with the second collision.Seat belt is the main components witch connect the occupant to the vehicle,its characteristics has a great effect on the protective for the occupant The traffic accident statistics show that airbags play a good protective effect only combine with the use of three-point seat belts.Data show that good performance of the three-point seat belts in the accident can prevent the occupant death with the rate of 41 percent,and combine use of seat belts and airbags to protect makes the rate to 46%.However,if the occupant just rely on the airbag without a seat belt as a result of the installation of the airbag,the accident death rate fell to about 20%.this paper optimize and design the parameters of the restraint system base on the energy management technology in order to have a good effect on the occupant's protection,2.Scope of PaperFirst,this paper describes the prototype of the vehicle collision test car on the basis of reading a large number of Chinese and foreign literature and regulations,particularly with regard to the standards and rules of NCAP.This paper establishes a prototype simulation model of car collision process by MADYMO6.3 and introduces the method of model correction and obtains a more accurate simulation model,which has been proved high accuracy and strong scalability results through comparison with test results and changing test conditions.Secondly,this paper introduces the occupant's energy distribution and consumption during the collision on the basis of energy management,and gives the information on energy calculation methods.It establishes a SIMULINKI mathematical calculations model.Thirdly,this paper establishes a simple collision model according to single degree freedom spring mass system,using the original vehicle test data to verify the effectiveness of energy analysis.This paper uses this model to analysis the stiffness of the restraint system's effect on energy distribution for the occupant,accelerate peak and the maximum relative displacement then analysis and compare various types of stiffness curve's effect on protection.Fourth,this paper analysis the original car's restraint system parameters based on the energy management technology and the studies of the stiffness in Chapterâ…¢.Fifth,this paper doing orthogonal optimal design to seat belt parameters and choose the best one from the result,that is,the parameters minimize the harm level of the occupant.3.Significance of Paper1,establishing the restraint system simulation model process by using of MADYMO. Through A large number of parameters correction work this paper establishes an effective and stable model for future simulation work.In this paper,correction of the model test data has great significant impact on the work of model correction,through the accumulation of research,summed up some of the laws of test data analysis can be used as reference for the study in the future.2,research and analysis of the energy consumption of the occupant in the collision process,the establishment of mathematical model by SIMULINK course with the energy-related data,in order analysis at a later stage3,this paper establishes a single degree freedom model of the collision to analysis the impact of occupant movement and energy by the occupant restraint stiffness,proposes the method of restraint system design and optimization witch can be effective in controlling the energy distribution.