In compliance with US Crash Standard FMVSS 208, from September 1, 1997 the Hybrid III dummy will be the only version permitted In the series of measurements conducted by several automobile companies, it has transpired that the hip joint exerts a negative influence on deceleration of the thorax This topic is also being investigated by SAE working groups Various petitions on this subject have already been filed with NHTSA
This paper analyzes the interaction of the thorax and thigh on the Hybrid III dummy in an effort to determine how far deceleration of the thorax is increased. Literature refers to this effect as “HIPLOCK” A series of sled tests is presented, in which the effect is visualized and the difference in the loads on the thorax for the Hybrid II, Hybrid III and Hybrid III dummy with modified thighs (bumpers) revealed
Hiplock does not occur on dummies which are secured by seat belts For this reason, all tests were conducted with dummies not restrained in this way Airbags and knee bolsters were used by way of restraint systems The test speed was 50 km/h The kinematic action of the pelvis was rendered visible in certain tests by cutting away part of the skin and foam which represent the dummy's “flesh”
