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The aim of this research was to find vehicle characteristics including stiffness that is effective for compatibility performance. Compatibility is said to be affected by three factors: vehicle mass, geometry and stiffness (1, 2). Of these factors, stiffness has more flexibility at the design stage than vehicle mass and geometry which are limited by the vehicle application. However, the stiffness is assumed to have a conflict issue between the self-protection and the partner-protection (3). In this research, it was analyzed comprehensively how some defined factors such as stiffness, mass, crash stroke and other vehicle characteristics indices relate to each occupant injury rate of the case and its partner vehicle in the real-world accidents. Both “front-to-front” and “front-to-side” crash occupants were covered.

This paper clarifies aggressivity reduction approach for MPV, Multi-Purpose Vehicles, derived from large passenger vehicles toward small passenger vehicles. The effects of aggressivity-reducing approach were measured through full-frontal rigid barrier crash simulations with TRL aluminum honeycomb by Finite Element Method. The front-end structures of large vehicles studied in this paper based on this aggressivity reduction approach show good front-end homogeneity and low average height of force. The structures were also found to effectively reduce aggressivity toward small vehicles by car-to-car simulation. However, there are some cases where the effect was influenced by overlap ratios. From this result, overlap ratio is considered to be one of the important factors to improve compatibility performance.

Driver fatality rate of a passenger vehicle is considerably high when struck on the side by an LTV (light truck and van). Aggressivity of LTVs, particularly in side crashes, needs to be reduced to improve this incompatible situation. Crash energy absorption share of a passenger car struck on the side by an LTV was measured through component tests. As a result, B-pillar of the struck passenger car was found to receive most of the crash energy intensively. This intensive energy triggered large B-pillar deformation. Computer simulation proved that B-pillar deformation was closely related to occupant injury. The key to mitigate the injury of side-struck car occupant, therefore, is to disperse crash energy to other structural parts than B-pillar. Front-end structures of LTVs that realize crash energy dispersion were designed and examined. The structures include (a) optimization of the vehicle height, and (b) adoption of a forward-extended sub-frame.

Developing an effective side impact ATD for assessing vehicle impact responses requires a method for evaluating that ATD's bio-fidelity. ISO/TR9790 has been in existence for some years to serve that purpose. Recently, NHTSA sponsored a research project on the post-mortem human subjects (PMHS) responses subjected to side impact conditions. Based on those newly available PMHS data, Maltese generated a new approach for creating bio-fidelity corridors for human surrogates. The approach incorporates the time factor into the evaluation equation and automates the process (Maltese et al. 2002). This paper serves as the first attempt to look closely at the new bio-fidelity corridor generation process (hereafter referred as the Maltese approach) with respect to its validity, effectiveness, as well as its practicality. The effect of mass scaling was first examined in order to ensure the integrity of the data. The time alignment scheme and the formation of the corridors were then tested.

For the purposes of analyzing and understanding the general effects of a set of different vehicle attributes on overall crash outcome a fleet model is used. It represents the impact response, in a one-dimensional sense, of two vehicle frontal crashes, across the frontal crash velocity spectrum. The parameters studied are vehicle mass, stiffness, intrusion, pulse shape and seatbelt usage. The vehicle impact response parameters are obtained from the NCAP tests. The fatality risk characterization, as a function of the seatbelt use and vehicle velocity, is obtained from the NASS database. The fatality risk is further mapped into average acceleration to allow for evaluation of the different vehicle impact response parameters. The results indicate that the effects of all the parameters are interconnected and none of them is independent. For example, the effect of vehicle mass on fatality risk depends on seatbelt use, vehicle stiffness, available crush, intrusion and pulse shape.

Continuous improvement of side airbag safety performance is an important step because it is associated with many public domain tests and regulations. Thus, occupant restraint with a side airbag is critical and it is necessary to develop tools that can be utilized to help in design of side airbags. Though many papers on side impact safety have been published, only a few papers are related to MADYMO simulations of side airbags. This paper describes an improved injury prediction and optimization approach using a MADYMO model for side impact. This model consists of 3 parts: dummy, trim and airbag in FEM. In this study, a side impact with a ES-2, EuroSID-2, was simulated in MADYMO as follows: First, component tests were conducted for trim and airbag respectively to establish correlation. Second, these component models were then integrated into a MADYMO model, which has high correlation with a crash simulator that is capable of replicating physical vehicle tests.

Of the injuries sustained by belted rear occupants in a frontal collision event in Japan, the neck and the head are the regions of the body most likely to be injured, while children and female occupants are accounting for the highest rate of injuries. For the purpose of reducing rear seat occupant injuries, the occurrence mechanism of neck and head injuries is clarified by sled tests with the current rear seat belt system. When a high load is applied to the occupant via the seat belt, the occupant experiences sudden deceleration of the chest, resulting in a great relative velocity difference between the head and the chest. This causes injury to the occupant's neck and head. To reduce occupant injuries, therefore, it is important to minimize the relative velocity difference by control of belt load.

Simple rigid body dynamics models are created to analyze the curb- and soil-trip types of rollover events and experimental methods that are used to simulate these events. Equations for the models are given, and they are integrated numerically to obtain the solution. Solutions of the models provide a break down of the energy during these events, which exposes the importance of energy absorption, unloading, and friction during the impact-and-roll process. Furthermore, the models are used to derive the critical sliding velocity under different test parameters. They are also used to understand near-critical state responses of the vehicle, and the corresponding characteristics of the signals in the phase space.

In order to secure effective occupant protection at vehicle collisions, it is necessary to conduct close examination into vehicle crash characteristics as well as interior parts, etc. This paper analyzes the behavior of a HYBRID III dummy restrained by three point seatbelt using MVMA2D computer simulation program at a 35 mph vehicle frontal barrier crash. As a result, it is found for good agreement between experiment and simulation that the exact input data of successive toeboard intrusion play an important role. As for the parametric study on vehicle crashworthiness, the authors propose the convenient method to represent the actual crash pulse by two simplified trapezoids. Then using these trapezoids, the parametric study clarifies the influence of vehicle deformation characteristics as well as the interior parts on dummy injury.