Study on Impact Response (Injury Value) Variation Factors for BioRID-II Dummies

The study aims to contribute to discussions for the standardization of BioRID-II dummies as an evaluation test tool, which is underway at the UN ECE/WP29/GRSP Head Restraint gtr Informal Meeting. Since it is important that as a test tool, BioRID-II be able to ensure a high repeatability and reproducibility, BioRID-II’s response variations in calibration and sled tests be examined using the following simulation techniques: First, to identify variation factors, a calibration test simulation model (MADYMO 7.2) was developed. In the simulation, three parameters (i.e., bumper characteristics, cable-spring characteristics, and damper characteristics) were varied in such a way that the prescribed corridor was satisfied and the resultant variations in acceleration, load, moment and other readings of BioRID-II were examined. Next, a sled test simulation model was developed, and using this simulation model, a similar parameter study was conducted for sled testing. The dummies' head acceleration, T1 acceleration, neck force and neck moment were measured. In addition, rotations of the head, neck and torso were also measured and analyzed. According to the simulation results, the calibration test generated the following variations in terms of CV values: 2~20% for rotation angle and 2~10% for acceleration, load and moment. On the other hand the sled test generated variations of: 2~15% for rotation angle and 2~15% for acceleration, load and moment. The data proves that the bumper, the cable spring, and the damper influence the impact response of the dummy’s rotation angle and injury value. Moreover, injury value variations proved practically identical between calibration and sled tests. Nevertheless clear differences between the two tests were found in the impact responses of respective rotation angles and injury values, also in the peak values and peak times. It was also found that these injury value variations can be minimized by approximation of impact responses and peak values, and by the synchronization of peak times between the two tests. Consequently it was considered necessary to introduce a calibration test method requiring seatback and head restraint conditions closely resembling that of the actual vehicle. This research compares the results of a calibration test and a ΔV16km/h sled test. The problem of determining what factors are affected by the calibration method of the BioRID-II dummy can now be defined. Moreover, the variation factor of the test conditions (dummy set, pulse, etc.) was also eliminated, and therefore only the cause of the variation of the dummy was studied. This analysis have yet to be reported until now, which makes such reports indispensable to the study of HR dynamic examination method of the UN ECE/WP29/GRSP. 1. Background At the UN ECE/WP29/GRSP, an Informal Working Group on development of Global technical regulation No.7 (“Head Restraint gtr Informal Meeting”) has been held since February 2005. Phase1 (it regulates as a standard requirement to the headrest about static backset (distance between the back of the head of a seated 3D mannequin and the head restraint)) was manufactured in March, 2008. Then, from December 2009, Phase2 of the Head Restraint gtr Informal Meeting (evaluation by dynamic test) was initiated. At the meeting, established was the evaluation by non geometric requirements called static backset but with a dummy injury value as a target. What was discussed was a target injury, a test method, etc. This currently, study focuses on dummy repeatability and reproducibility for use in regulation. Japan Automobile Research Institute (JARI) and Japan Automobile Manufacturers Association (JAMA) has been studying()() the test evaluation method which can reduce the neck injury generated during vehicle accident, and this testing method is to be proposed to Japan or other countries. As part of the research, injury value variation generated in evaluation test is examined. Various factors, such as variations in test conditions (impact acceleration, a dummy arrangement, etc.) and the individual differences of dummies or sheet, are included in injury value variation. This research particularly focused on whether or not injury value variation in calibration testing affects dummy responses in rear impact sled test. More specifically, analysis of the simulation of calibration test and Sled test was