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Implementation of appropriate safety measures, either from the viewpoint of a vehicle or the society or the infra-structure, it is an important issue to clearly understand the multi-dimension complicated real world accident scenarios. This study proposes a new method to easily capture and to extract the essence of such complicated multi-dimension mutual relationship by visualizing the results of SOM (Self Organizing Map). The FARS data from 2010 is used to generate a dataset comprised of 16,180 fatal passenger car drivers and 48 variables. The 16,180 fatal drivers were clustered using hierarchy cluster analysis method and mapped into a two-dimensional square with one dot representing one fatal driver using SOM.

Occupant protection performance in frontal crashes has been developed and assessed for mainly front seat occupants over many years, and in recent years protection of rear seat occupants has also been extensively discussed. Unlike the front seats, the rear seats are often occupied by children seated in rear- facing or forward - facing child restraint systems, or booster seats. In the European New Car Assessment Program (NCAP), child occupant protection assessments using 18-month-old and 3-year-old test dummies in the rear seat are already being conducted. In addition, studies are under way concerning the development and introduction of test dummies of 6-year-old (6YO) and 10.5-year-old children. In this study, we focused on 6-year-old children sitting in belt-positioning booster seats. Offset frontal crash tests were conducted using two types of test dummies, a Hybrid III 6YO and a 6YO Q-series dummy (Q6), positioned in the rear seat.

In general, the improvement of vehicle body stiffness involves a trade-off with the body weight. The objective of this research is to derive the lightest-weight solution from the original vehicle model by finding the optimized spot-weld layout and body panel thickness, while keeping the body stiffness and number of spot welds constant. As the first step, a method of deriving the optimal layout of spot welds for maximizing body stiffness was developed by applying the topology optimization method. While this method is generally used in shape optimization of continuous solid structures, it was applied to discontinuous spot-weld positions in this work. As a result, the effect of the spot-weld layout on body stiffness was clarified. In the case of the body used for this research, body stiffness was improved by about 10% with respect to torsion and vertical and lateral bending.