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Load-limiting belt restraints have been present in French cars since 1995. An accident study showed the greater effectiveness in thorax injury prevention using a 4 kN load limiter belt with an airbag than using a 6 kN load limiter belt without airbag. The criteria for thoracic tolerance used in regulatory testing is the sternal deflection for all restraint types, belt and/or airbag restraint. This criterion does not assess the effectiveness of the restraint 4 kN load limiter belt with airbag observed in accidentology. To improve the understanding of thoracic tolerance, frontal sled crashes were performed using the Hybrid III and THOR dummies and PMHS. The sled configuration and the deceleration law correspond to those observed in the accident study. Restraint conditions evaluated are the 6 kN load-limiting belt and the 4 kN load-limiting belt with an airbag. Loads between the occupant and the sled environment were recorded.

This study was conducted to address injury risk due to high-speed loading of the abdomen by a seatbelt during the pretension phase. Indeed, a better coupling of occupants to the structure of the vehicle in frontal impact can be achieved by a strong pretension of the lap belt. However, out of position considerations have to be taken into account in the development of pretension systems. In particular, when the lap belt is on the abdomen instead of the pelvis at the time of pretension, the penetration of the belt into the abdomen should not lead to injuries. Given the sensitivity of pyrotechnic pre-tensioners to the resistance that they encounter, it is important to have an understanding of the behaviors of both human and dummy abdomens in order to evaluate injury risk. These data are indispensable for the evaluation, with dummy tests, of the effects of pre-tensioners on occupants and for the estimation of the levels of injury risk.

The accidentological studies dealing with automotive side collisions suggest that the pelvis is very vulnerable. Car manufacturers are more and more concerned with the protection of the occupant in lateral impact, but there is a lack of knowledge of the behavior of the pelvic bony structure and of its biomechanical tolerances. This knowledge however is essential in order to optimize protection devices and car structures with regard to the security of the occupants. The main goal of this study is thus two-fold: First, a field accident analysis was carried out in order to document the lesions and the injury mechanisms encountered in lateral impact. The accident database of the Laboratory of Accidentology and Biomechanics (LAB) was used and a sample of 219 injured occupants sustaining 381 injuries in lateral collision enables to evaluate the most frequent injuries and their location. Those injuries were also analyzed with regard to the car characteristics.

Accident studies show that frontal collisions, both as regards the number of people killed and those seriously-injured, are by far the type of crash with the most serious consequences. In order to improve this situation, it is necessary to ensure that the means used to restrain occupants work as efficiently as possible, whilst preserving the occupant compartment and thus by eliminating intrusion on the occupant restrained by seat-belts and pretensioners. In frontal collisions where vehicle intrusion is minor, the main lesions caused to occupantss are thoracic, mainly rib fractures resulting from the seat-belt. In collisions where intrusion is substantial, the lower members are particularly vulnerable. In the coming years, we will see developments which include more solidly-built cars, as offset crash test procedures are widely used to evaluate the passive safety of production vehicles.

This paper presents comprehensive dorsiflexion responses and tolerances obtained from two types of dynamic tests on whole cadavers conducted at the Renault/PSA Laboratory of Accidentology and Biomechanics (LAB): sled tests and sub-system tests. In all the experiments (on whole cadavers), forces and moments within the ankle joint were accurately measured by means of a custom-designed 6-axis load cell implanted in the tibia, leaving all surrounding musculature intact. The results derived from both the sled tests and the subsystem tests are very similar. Moment-rotation curves are provided for the ankle joint. The force in the Achilles tendon which is not directly measured is calculated using the forces applied to the foot and the forces measured in the tibia.

The anatomical dimensions, inertial properties, and mechanical responses of cadaver leg, foot, and ankle specimens were evaluated relative to those of human volunteers and current anthropometric test devices. Dummy designs tested included the Hybrid III, Hybrid III with soft joint stops, ALEX I, and the GM/FTSS lower limbs. Static and dynamic tests of the leg, foot, and ankle were conducted at the laboratories of the Renault Biomedical Research Department and the University of Virginia. The inertial and geometric properties of the dummy lower limbs were measured and compared with cadaver properties and published volunteer values. Compression tests of the leg were performed using static and dynamic loading to determine compliance of the foot and ankle. Quasi-static rotational properties for dorsiflexion and inversion/eversion motion were obtained for the dummy, cadaver, and volunteer joints of the hindfoot.