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In order to investigate pedestrian injury mechanism by representing whole body kinematics of a pedestrian, a pedestrian dummy (POLAR II) has been developed. Previous studies indicated that the original pelvis design needed to be modified from the comparison of POLAR II and PMHS (Post Mortem Human Subject) responses in a pedestrian impact test with a SUV (Sports Utility Vehicle). In addition, according to the results of an in-depth investigation of pedestrian versus SUV or mini-van accidents in the US, pelvis fracture was found to be most frequent in AIS 2+ pelvis and lower limb injuries. Based on these findings, the POLAR II pelvis was modified for improved biofidelity. The modified pelvis design incorporated the flexible ilium (polyacetal resin) and pubic symphysis (rubber material) as opposed to the original pelvis cast in aluminum. The modified pelvis responses were verified against published isolated pelvic PMHS test results in lateral compression of the pelvis.

Pedestrian - motor vehicle collisions account for approximately 15% of all traffic fatalities in Europe and the US, and 35% or more in Japan and Asian countries. Several studies have addressed this issue, such as the EEVC study. In the development of the test methods, body region priorities are mainly based on studies of pedestrian collisions with passenger vehicles. However recently, the populations of SUVs and LTVs are increasing in many countries. Pedestrian collision data indicate that thoracic and upper abdominal injuries are also frequent in pedestrian collisions where these kinds of vehicles are involved. However, evaluation methods for pedestrian torso injuries are not currently available. This paper describes a study for the evaluation of pedestrian thoracic and upper abdominal injuries using the POLAR II pedestrian dummy.

In order to enhance understanding of pedestrian injury mechanisms, full-body pedestrian dummies have been developed in past studies. The goal of this study was to estimate knee ligament injury measures for a pedestrian dummy based on the correlation between dummy and human responses. For estimating knee ligament force of the dummy approximating the average ligament failure, finite element (FE) human and dummy knee joint models were subjected to dynamic 4-point bending. The estimated measures for the modified dummy knee ligaments were 3.0, 0.5 and 1.1 kN for the MCL, PCL and ACL, respectively. A full-body FE dummy model was subjected to impacts from a small sedan and a Sport Utility Vehicle (SUV) for validating the estimated force levels. The results showed that the estimated dummy knee ligament force levels predicted failure of human knee ligaments that is likely to take place first when leg fractures are not present in impacts from a small sedan and a SUV.

Experimental tests were performed on the modified Polar-II pedestrian dummy lower extremity components to evaluate their biofidelity in lateral impact loading corresponding to a 40 km/h pedestrian-car collision. The bending moment-angle response from a newly developed knee joint, dynamically loaded in four-point valgus bending, was compared against previously published postmortem human subject (PMHS) response corridors. In addition to the stiffness characteristics of the knee joint, individual ligament forces were also recorded during the bending tests. The evaluated force-relative elongation response of the medial collateral ligament (MCL) in the new knee was compared against PMHS data on MCL tensile stiffness. Lower extremity long bones developed for improved anthropometrical accuracy and deformability were dynamically loaded in latero-medial three-point bending.

The goal of this study was to develop and validate a finite element (FE) model of the Polar-II pedestrian dummy. An upper body model consisting of the head, neck, shoulder, thorax, and abdomen was coupled with a previously validated model of the lower limb The viscoelastic material properties of the dummy components were determined from dynamic compression tests of shoulder urethane, shoulder rubber and abdominal foam. For validation of the entire upper body, the model was compared with NHTSA response requirements for their advanced frontal dummy (Thor) including head and neck pendulum tests as well as ribcage and abdominal impact tests. In addition, the Polar-II full body FE model was subjected to simulated vehicle-pedestrian impacts that recreated published experiments. Simulated head and pelvis accelerations as well as upper body trajectories reasonably reproduced the experiment.

A new pedestrian dummy, called ""POLAR'' has been recently developed. It can be used as a tool not only for the investigation of the mechanism of pedestrian accidents, but also for the assessment of vehicle aggressiveness to pedestrians. This dummy is modified from "'THOR,'' new- generation occupant dummy, in its body structure to reproduce human body kinematics in the event of collision with a vehicle more precisely. Its knee has a human-like structure, with condyles which shape is similar to that of human knee, meniscus, cruciate ligaments and collateral ligaments. Tibias of Polar are made of urethane which bending characteristic is that of human tibia. These features not only make the lateral bending and shearing responses of the leg and knee more human-like but also the whole body kinematics more human- like.

The upper leg component test proposed by EEVC WG17 is one of the tools for the evaluation of upper leg injuries in pedestrian accidents. Meeting the injury criteria set by EEVC for the upper legform impact test is one of the biggest challenges we can find in the reports. This problem was studied in previous papers using simulation models or reconstruction of pedestrian accidents. The POLAR pedestrian dummy was constructed by HONDA R&D and GESAC INC., and some crash tests were conducted with it. The object of this study is to compare EEVC WG17 upper legform impact test conditions for utility vehicles with the full dummy test results. To reconstruct the deformation resulting from tests using the POLAR, the impact energy for the EEVC upper legform impact test should be decreased. Even the upper limit of 700J is too high. Accident data analysis shows that the pelvis is the body part injured by the bonnet leading edge of the utility vehicle.

Honda has been studying ways of improving vehicle design to reduce the severity of pedestrian injury. Full-scale test using a pedestrian dummy is an important way to assess the aggressiveness of a vehicle to pedestrians. However, from test results it is concluded that current pedestrian dummies have stiffer characteristics than Post Mortem Human Subjects (PMHS). Also, the dummy kinematics during a collision is different from that of a human body. Because of the limitations of current dummies, it was decided to develop a new pedestrian dummy. At the first stage of the project, a computer simulation model that represented the PMHS tests was developed. Joint characteristics obtained from the simulation model were used in building a new pedestrian dummy which has been named Polar I. The advanced frontal crash test dummy, known as Thor, was selected as the base dummy. Modifications were made for the thorax, spine, knee etc.