Reliability of the KPSIT C50 dummy's cervical joint in cyclic tests for low-speed collisions up to 20 km/h

The durability and stability of the cervical joint system of the KPSIT C50 crash dummy were evaluated. The two-element neck module has two degrees of freedom, enabling flexion-extension and right-left rotation. Drag torque characteristics were measured on a test bench using the point method, combining force and angular deflection measurements and compared with the Hybrid III reference dummy in the usable range. Durability was assessed in 200 crash tests over 24 months, with drag torque checked every 25 tests. No major parameter changes were found up to 75 tests. From about 100 tests, drag torque gradually decreased, mainly in the extreme motion zones. After 200 tests, the maximum reduction reached about 15% in flexion-extension and about 12% and 10% in rotation, while values in the central range remained stable. A 20 km/h frontal collision test showed larger head displacements after the program, indicating moderate growth in cervical compliance without loss of repeatability. The results confirm suitability for low-spin tests and support periodic torque checks after about 100 crashes.