Sensitivity Analysis And Study On Structural Optimization Of Automobile Seat

With the world's energy issues outstanding, energy saving, environmental protection and reduce fuel consumption has become the automobile manufacturer pursue goal. In automobile structural design, in order to meet the performance requirements of motor vehicles, advanced lightweight design concept is very important. The seat of the car is the parts that person gets in touch with directly, its comfort and safety research also start being value by the automobile customer and the manufacturers.Similar to other product design, the design of seating systems is basic on the requirement of people.Thus, the study on seat can divide into two branches:the research on seat safety and the research on seat comfort. The research on safety focuses on the static performance, the fatigue strength and the performance during impact of seat. And the research on comfort includes the body's static mass distribution, the seated position, the performance of absorbing vibrations and aspect of optimization. With the development of the IT, FEM is widely used in the area and has become one of the most important methods.Based on the above, The authord considering, in the future, the seat must become more light, intelligent and humanistic. Thus, the FEM and topology optimization will be the most powerful tools. Realized the vehicle seat's lightweight way mainly to have three kinds:One is use of the new low density materials, such as aluminum, magnesium alloy or composite materials etc. Second, through the optimization of the structure size, shape optimization of the structure and topology optimization to reduce weight. Third, new manufacture process technology, like special-purpose welding technique, special-purpose machinery tight part and so on. To let the seat more intelligent is to make seat adjust the seatback angel and seat's temperature automatically according to every occupants'need. The aim of seat humanistic design is to let the system of"people– seat"more harmonious and reasonable.The main work of this paper is as follows:In explaining the basic theory of sensitivity analysis and finite element modeling on the basis of key technologies. Take the domestically produced passenger vehicle chair skeleton as the example, introduced the general method of structural optimization and sensitivity analysis by using the finite element method. According to this topic's research projects, select the appropriate unit type, the restraint and the load way to establish this seat skeleton's finite element model. According to the code GB15083-1994,GB11550-1995, using software named HyperMesh, carries on the static state, the dynamic simulation analysis and sensitivity analysis, obtains the seat skeleton lightweight clue, then using the obtains clue optimizes the unreasonable structure in the seat structural design process.In chapter 1, based on reading of a mass of literature, I simply introduced the domestic and foreign seat's research technique and the trend of its development, the development that obtained the achievements and most recent development tendency of the new seat. This article has reviewed the automobile seat security, comfortable aspect of research content and the method.In chapter 2, in view of the seat's mechanical properties optimized specific issues,introducing the sensitivity analysis of the finite element based on the response sensitivity analysis.In chapter 3, discussing the process of founding FEM seat model, and founding model's every detail and method, it offers anterior preparative job for right analyzing the seat. Following FEM principle, found FEM seat modal framework in details by software Altair HyperMesh.In chapter 4, under the guidance of China's car seat safety regulations, based on the finite element model of seat structure, static strength analysis and the first-order modality analysis were done. The simulation results showed that this seat skeleton satisfy the regulations the request, and the simulation result has provided the performance restraint for the following optimization.In chapter 5, the static rigidity and the first-order reverse frequency sector analysis using the Optistruct software on this seat model were done, and on the basis of conventional optimization sensitivity analysis. Then, choosing design variable due to the sensitivity analysis result to define the optimization model, and carries on the size optimization to this seat structure.The seat performance before and after optimization model comparison showed that the proposed method of optimization achieved good results.Finally, I has made the summary and the forecast to the entire article.The significances of this paper are:Firstly, using finite element software HyperMesh carry on the static and dynamic characteristics of the general process to the model, based on the study in this paper, the finite element analysis method of static performance of seat structure was summarized and provided other people some useful experience.Secondly, the paper made some research on the structure of seat using Optistruct, which started a new period of seat safety research.Thirdly, the result of reasearch in this paper showed that by reck on the effect of relative sensitivity in the optimization design can bring quickly efficiency.The work done in this paper also has referencing value on solving the conflict problem of optimization targets existed in the multi- targets optimization design.