Research On Comfort And Structure Improvement Of Driver's Seat Based On Fine FE Model

Automotive seat comfort has become an important indicator in the development of seat.The current development of seat comfort verification is mainly based on a large number of experienced technical staff to carry out field test,subjective evaluation,and to measure body pressure distribution.Reasonable body pressure distribution indicates a good seat ride comfort.Combining with advanced CAE technology to fully reflect the seat comfort by the finite element analysis seat model,automaker can achieve a time-saving and cost-saving purpose.The key factors that affect the seat static comfort are the mechanical properties of the foam and fabric cover under static compression and stretch.It is necessary to establish an accurate test method to measure the mechanical properties of the foam and the seat fabric cover.The mechanical properties of the foam and fabric cover were tested in three sets of seats.The static compression and constant speed tensile tests of the foam were conducted,which takes the stress relaxation characteristics of the foam into account,and the static strain was measured until the foam strain reaching the 80%,.In order to verify foam material model,FEA model are established.The simulation results show that the stress strain curves are in good agreement with the experimental results.The fiber warp,fiber weft,and the two diagonal tensile mechanical properties are tested,which provides the data with the simulation of the seat cover.The seat fine model is established in conjunction with the data,which includes constraints between the frame,the foam,the seat cover and other components,these features tell the difference between the common model and fine model.The necessity of establishing the seat fine model is further illustrated by comparing the H point data and the body pressure distribution of seat and the simulation results.Integrating existing research results,the methods of evaluating the body pressure distribution are established,such as the maximum pressure and the pressure gradient and mean pressure.The crucial factors that influence the distribution of the comfort of the seat comfort are analyzed on the basis of the fine seat model.Crucial factors include the foam loading curve,the foam thickness of the cushion and backrest,the foam length of the cushion,the angles of seat cushion and backrest,lumbar support,multi-hardness foam and so on.According to the conclusion of the analysis,the basic structure of seat model is improved.By drawing a comparison about body pressure distribution between original model with improved model,the improvement of seat is tested.And combined with the role of the seat development process that CAE technology play in,one development process of the seat comfort in the initial stage of the seat development is presented.