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A new approach has been developed to facilitate the measurement of head angular acceleration in automobile crash tests. It consists of two parts: an array of 12 linear accelerometers mounted in a Hybrid III dummy head and an electronic signal processor mounted on the dummy spine. The accelerometer outputs are led to conventional data acquisition equipment and also to the signal processor which digitizes the raw acceleration signals, stores them, and computes the 3-D angular acceleration. This acceleration and the 3-D linear acceleration of the head c.g. are available in real time or post test. The equipment has been evaluated on a mini-sled, with various configurations of head loading and kinematics, and also in Hyge sled tests performed at 40 km/h with a 3 point belted Hybrid III dummy. The angular accelerations returned by the signal processor in both test settings corresponded closely to those computed off-line from the raw data.

Determining the angular acceleration of the head in automotive safety tests is one of the most important aspects of research on brain tolerance. For this purpose, a methodology combining various software packages and a specific accelerometer device has been developed at LPB-APR. The aim of the present publication is to evaluate this methodology for a variety of test-crash configurations, with or without head impact, i.e. frontal sled tests, steering wheel impacts and drop tests. The key feature of this study is the computing potential made possible by an accelerometer mount designed for the head of the Hybrid III dummy. In particular, the methodology developed allowed high angular acceleration levels to be computed, i.e. more than 15.000 rad/s2 in steering wheel impact. To confirm the results, examples of computing-measurement validation are given for each impact situation analyzed.