In the EC FP6 Integrated Project APROSYS, the first WorldSID small female prototype was developed and evaluated by BASt, FTSS, INRETS, TRL and UPM-INSIA. Results were presented at the ESV 2007 conference (Been et al., 2007[1]). A concern was raised that the current chest deflection measurement system, IR-Traccs, registered flat top responses and sometimes may not register the peak deflection. This was believed to be related to forward deformation of the ribs relative to the spine and associated extension of the IR-Traccs. In the mean time an update version of the dummy, called Revision1, was developed to address the issues found in the first evaluation round.

To improve oblique thorax loading sensitivity, a two-dimensional chest deflection sensor, the 2D IRTracc was developed. Measuring the angle between the spine box and the IR-Tracc enables the displacement of the most lateral point on the rib rib to be calculated in the XY (transverse) plane. To evaluate the new system, FTSS conducted single rib unit tests on a drop tower under pure lateral and oblique test conditions. The compression and rotation data were analysed to find the displacement of the most lateral part of the rib, and the rib deformation in the impact area. In addition, TRL subjected a complete Revision1 prototype dummy to oblique thorax pendulum tests and LAB conducted full dummy static deployment airbag tests under various impact angles and impact severities.

The 2D IR-Tracc proved to be very useful in understanding phenomena taking place under various lateral and oblique impact conditions that could not have been understood with the current (1D) compression sensor alone. The reduced sensitivity of the conventional IR-Tracc (Dy rib) to oblique impact was confirmed in this study. The calculated lateral displacement Y offered a simple and straightforward parameter to improve the sensitivity to oblique impacts, as compared to the current single axis deflection sensor.