Automotive Seat Structure Safety Design And Optimization

Car is more and more popular these years and consumers begin to pay more attention on safety performance. All the car makers in China and foreign countries put car safety in the first role in their business running. The safety performance of the car not only depends on chassis and car body but also depend on the interior systems and they play a key role during the high speed crash. Car seat provides passenger comfort space during the driving and safe space when crash happened.With the developing of finite elements analysis car makers begin to utilize FEA tool to perform crash simulation before real physical sled test, such as front impact and rear impact. The author utilizes LS-DYNA code conducts luggage retention analysis for second row seat according to the Chinese GB-15083 standard. Through the FEA to physical test result correlation, good result matching proves it is feasible to use current process and method to simulate luggage retention analysis with LS-DYNA code. Rely on this baseline the author perform further optimization for seat back frame and ensure the new seat structures pass the test at first time.In chapter 1, it presents an overview of current safety status about cars. It describes the functions of seat system that is it provides passenger comfort space during the driving and safe space when crash happened. About safety standards it describes the requirements of China, North America and Euro and also current safety status in China. At the end of this chapter it introduces the application of finite elements analysis in car safety design and research direction of this paper.In chapter 2, it illustrates general static and dynamic test methods according to each safety standard in details. It covers seat H-point moment test method, seat head restraint energy absorbing test, seat safety belt anchorage strength test, luggage retention impact test and high speed sled test In chapter 2, it describes how to use HYPERMESH pre-processing software to create seat FE model in details, such as boundary setting-up rules and parameters selection. And then LS-DYNA code is used to run calculation. The FEA result match the physical test result well and verify the feasibility to use current process and LS-DYNA code to predict seat performance during the high speed crash.In chapter 4, author made a further study about the factors that impact the seat performance. Total 6 factors are being investigated: 1) Sled acceleration pulse; 2) The distance between block and seat back frame; 3) The latch location related to car body; 4) body in white structure; 5) The vertical distance from floor to seat back rotary axes; 6) Friction coefficient of car floor. Through the study on these 6 factors it provides seat designer valuable reference.In chapter 5, optimization for current rear seat structure is performed. During the structure optimization Topography is used to detect the tube connection way, load distribution path is being investigated base on mechanical theory. The new structure after optimization passes the real physical test at one test.In the chapter 6, summary and discussion about following task can be carried on.The value of this paper:1, describing the general physical test method in details and showing lots of test photos that is easy to make reader to understand test information.2,describing the luggage retention simulation procedure and compare the FEA result with physical test, good result matching is got. So it presents useful information and skills to the engineers who did not know how to perform analysis for seating system.3,investigating the main 5 factors that impact the seat performance in the luggage retention test. And each factor of total 5 is discussed in details that will give seat designer a valuable reference for their current or future seat back design to deal with rear crash test.4,utilizing OPTISTRUCT software and load distribution path to analysis the seat back frame in all approach, show reader a valuable case and meaningful reference...