# Verification of Automotive Monopost Seat Strength through Dynamic and Quasi-Static Simulations
## 1 Introduction  
As the number of vehicles on the road increases, environmental and energy problems increase because of exhaust emissions and excessive oil use. In recent years, electric vehicles have steadily replaced traditional vehicles with internal combustion engines. The floor space of an electric vehicle is more extensive and stable than a standard internal combustion engine vehicle because of the absence of drive shafts. Despite this, the internal space cannot be fully utilized because the seat frame structure, which occupies most of the internal area, is unchanged. The total weight of an electric vehicle has a significant influence on its mileage. Hence, a change in the internal structure is required to utilize the internal space better and reduce its weight. Automotive seats occupy a significant amount of interior space and account for 3-5% of the vehicular weight [1]. Therefore, improvements to standard seats are required. In standard automobile seats, a square-shaped frame closely connects a cushion part to a floorboard. The space under the cushion cannot be utilized, and the seat structure occupies most of the space inside the vehicle. The limited internal space of a vehicle can be innovatively improved by increasing the openness and spaciousness by applying a monopost columnar structure instead of the traditional square frame. By setting a columnar monopost structure between the rail and the floorboard of a vehicle, cushions can be separated from the floorboard, and the space under the seats can be used, increasing passengers' perception of openness and spaciousness. The National Highway Traffic Safety Administration (NHTSA) website provides vehicle collision models,and the 2019 Honda Odyssey model is freely downloadable [2]. Figure 1 presents a seat in the 2019 Honda Odyssey and the space available under a monopost seat. Monopost seats are thinner and lighter than standard seats because they use novel materials. Vehicle seats provide passengers with ride comfort and safety in collision events. Nevertheless, they should be sufficiently sturdy and lightweight, and should provide increased freedom of movement. [PERSON] et al. (2014) evaluated the passenger protection capacity of seats in front- and rear-end collisions using LS-DYNA. The simulation results indicated that structural modifications were necessary to ensure passenger safety. Four improvements were made to the seat structure based on the seat stress analysis, the seat side panel, center hinge, seat bottom frame, and backrest lock. A passenger model sustained fewer injuries when the re-designed seats were re-simulated [3]. [PERSON] et al. (2017) examined an automobile seat with a focus on seat belt fastening and sliding parts, using LS-DYNA, in accordance with GB14167-2013 national standards [4]. The re-designed and finally optimized seat met regulatory standards [5]. In compliance with ECER1414 requirements, [PERSON] et al. (2019) examined the effects of the material type, thickness, and cross-sectional symmetry on the strength of an automobile seat slider, where the material type demonstrated the most significant effect. The increase in material strength compensated for the decrease in strength caused by the thinner cross-section when S700 MC material was used. In addition, the symmetry/asymmetry of the cross-section had a negligible effect [6]. [PERSON] et al. (2021) assessed a design method for a lighter front seat rail. A built-in stand pipe that can replace a single set of existing stands for an automobile seat rail was developed. The final model passed a crash test and was 26.7% lighter than a standard seat [7]. [PERSON] et al. (2018) performed a strength test on a motor seat frame made for commercial vehicles weighing one ton, in order to identify its vulnerable regions. The experiment conducted on the seat frame strength followed the FMVSS210 test standard and was conducted using ANSYS software.