In a seat design in terms of structural integrity, main load carrying components are track part and the locking system. In this thesis, a finite element modeling of a vehicle seat system for stress analysis and an optimal design formulation of the main components are presented. Numerical solutions are obtained for specific loading cases.
A commercial code, ABAQUS, is utilized forthe linear elastic stress analysis. Two optimal design formulations, either to minimize the maximum stress or to minimize the volume, are considered under volume or stress constraints. As for the design load, loading specifications from FMVSS and a test load from an industry are considered. Three extreme seat positions are taken to impose stress constraints or to find the maximum stress under a multiple loading situation.
Optimal designs corresponding to various formulations and different selections of design variables are obtained. It is found that the stress in the present design is high compared to the material strengths. Similarly the maximum stress under the volume constraint of the present design also exceeds the material strengths, although it has been reduced much from the optimization. This means that the loading conditions used are too harsh and may not be suitable as a design load using linear elastic analysis. The results, however, have provided the trend of the optimal designs and the influences of various design variables. The thickness is more sensitive to the optimum designs than the width or the depth. It is concluded that the modeling and the optimal design formulations are suitable for the analysis and design of the vehicle seat system, provided that appropriate loading conditions are specified from other studies.
