Abstract
A Minicar is a micro mobility, that is expected to have widespread use in the future. It is suitable for the transportation of elderly people and for deliveries because of its small size and single seat. However, collision safety of a minicar has not been reported. Because a minicar is smaller than small cars, so it is difficult to secure an enough crashable zone. Therefore, in frontal collision of a minicar, the cabin may be largely deformed and the steering wheel collide with the occupant. Occupant injury occurs because of the collision with the steering wheel. In previous studies, a full frontal rigid barrier impact test using a minicar was conducted （initial speed 55 km/h） and the problem of minicar in frontal collision were clarified. The steering wheel retreated and collided with the occupant because of the large deformation of the body frame. Therefore, occupant face a high risk of injury. Therefore, in this study, a full frontal rigid barrier impact test was simulated using the finite element model reproducing the front body frame and chassis structure of the experimental vehicle, and the multi-body model reproducing the interior parts and the occupant. To reduce the occupant injury by improving the body frame structure, deformation of the cabin was suppressed by increasing the rigidity of the front frame. On the other hand, the maximum acceleration was increased because of the high rigidity of front frame. Therefore, the maximum deceleration was suppressed by equipping the crushable box. In addition, the restraint force of the seat belt was adjusted to avoid the collision between the steering wheel and the chest by adding a seat belt pretensioner and a force limiter. Two consecutive improvement to the body structure and occupant restraint method were enforced, and then chest deflection and HIC36 as a head injury index reduced below injury criterion.
