Research On Methodology Of Seat Comfort Design Based On Body Pressure Distribution

Seat is one of the most important automobile parts which contact frequently withpassenger. The seat comfort not only affects the automobile’s competitiveness but also hasan important influence on passenger’s health and driving safety. The appearance of the seat,geometric size, mechanical function and the characteristics of mechanics of materials haveimportant influences on seat comfort, and the influences of above factors on the seat comfortcan be explained by the BPD(Body Pressure Distribution) between seat and passenger.Different parts of human body have the different capacity to endure pressure, so each part ofhuman body has a comfort pressure range. No matter higher or lower than this range, it willmake passenger feel uncomfortable. Researchers can know whether the design is reasonableby using BPD which is helpful to improve the seat comfort. Therefore an increasing numberof researchers study and improve the seat comfort by using BPD.Seat comfort subjective evaluation experiment and simulation experiment of BPD arethe most commonly used research methods. Subjective evaluation experiment is the mostdirect reflection of seat comfort as it reflects volunteers’ true feelings about the seat.Simulation experiment of BPD can obtain the pressure distribution data by using seat andhuman FE model. Compare with subjective evaluation experiment, the simulationexperiment not only spend less time and money, but also can get rid of affect which comesfrom objective factors. But the result must be referenced to subjective evaluation experimentresult, or it is meaningless. This article took the simulation experiment as the main methodof studying seat comfort based on the current experiment conditions.In order to obtain accurate results, basically there were two difficulties need to payattention to. The FE model should reflect the detailed characteristics of body and seat as faras possible, especially the mechanical properties and appearance characteristics. The detailedhuman body geometric model established by reverse engineering based on body point cloud data and body size prediction analyzed by principal component analysis. Then the geometricmodel’s posture were adjusted by CPM which integration in Catia. The FE model of humanbody established based on the geometric model. The seat FE model established based on aseat geometric model which simplified from a detailed seat model. FE model’s materialproperties, boundary conditions and loading method were important to the accuracy of theresults. In order to guarantee the accuracy of the simulation experiment result, all thesefactors were set by according to the actual situation and reference of scholars’researches.In order to study whether H point device can measure basic parameters of seat throughsimulation experiment, this article carried on simulation experiment by using H point deviceFE model. It was also carried on simulation experiment focus on the influences of thicknessof seat foam, seat lumbar support and seat angle on seat comfort. All the results wereanalyzed by BPD index which including maximum pressure, contact area, human soft tissuestress. Four sections were also defined to obtain the pressure distribution along the sectionwhich can be used to study the seat comfort. All the experiment results proved that theinfluences of above factors on seat comfort can be explained by the BPD.A new seat comfort evaluation model was put forward in this article by summarizingthe advantages and disadvantages of many comfort evaluation models. The capacity toendure pressure was considered in the model. The model used local smoothing andnormalized data processing method to process the BPD data. The evaluation result wasestablished by AHP method through evaluating the degree of variance between ideal BPDand actual BPD which can define the seat comfort level. Nine simulation experiments werecarried on in this research. The results proved the model can evaluate seat comfort accuratelyand properly.