Abstract: Thorax compressed distortion in frontal crash tests is an important appraisal for vehicle safety
according to the China New Car Appraise Program (C-NCAP). In current frontal crash dummy tests, different
rib inconsistent performance may lead to different data of the thorax compression. This paper investigates the
influence of dummy rib stiffness characteristics and their differences on the chest compression deformation
through calibrating frontal impact tests for two 50th percentile Hybrid-III male dummies, and revising the
sensitivity coefficient of chest displacement sensors in the calibrating measurement. The results indicate
that revising sensitivity coefficient can eliminate the differences caused by rib stiffness characteristics.
Therefore, this method can improve the test accuracy, strongly supporting the vehicle constraint system
development.

Key words: vehicle safety, frontal impact, dummy rib, rib stiffness, displacement sensor, sensitivity coefficient, vehicle constraint system