Whole-body response to pure lateral impact.

The objective of the current study was to provide a comprehensive characterization of human biomechanical response to whole-body, lateral impact. Three approximately 50th-percentile adult male PMHS were subjected to right-side pure lateral impacts at 4.3 ± 0.1 m/s using a rigid wall mounted to a rail-mounted sled. Each subject was positioned on a rigid seat and held stationary by a system of tethers until immediately prior to being impacted by the moving wall with 100 mm pelvic offset. Displacement data were obtained using an optoelectronic stereophotogrammetric system that was used to track the 3D motions of the impacting wall sled; seat sled, and reflective targets secured to the head, spine, extremities, ribcage, and shoulder complex of each subject. Kinematic data were also recorded using 3-axis accelerometer cubes secured to the head, pelvis, and spine at the levels of T1, T6, T11, and L3. Chest deformation in the transverse plane was recorded using a single chestband. Following the impact the subject was captured in an energy-absorbing net that provided a controlled non-injurious deceleration. The wall maintained nearly constant velocity throughout the impact event. One of the tested subjects sustained 16 rib fractures as well as injury to the struck shoulder while the other two tested subjects sustained no injuries. The collected response data suggest that the shoulder injury may have contributed to the rib fractures in the injured subject. The results suggest that the shoulder presents a substantial load path and may play an important role in transmitting lateral forces to the spine, shielding and protecting the ribcage. This characterization of whole-body, lateral impact response provides quantified subject responses and boundary condition interactions that are currently unavailable for whole-body, lateral impacts at impact speeds less than 6.7 m/s.

Impact response of restrained PMHS in frontal sled tests: skeletal deformation patterns under seat belt loading.

This study evaluated the response of restrained post-mortem human subjects (PMHS) in 40 km/h frontal sled tests. Eight male PMHS were restrained on a rigid planar seat by a custom 3-point shoulder and lap belt. A video motion tracking system measured three-dimensional trajectories of multiple skeletal sites on the torso allowing quantification of ribcage deformation. Anterior and superior displacement of the lower ribcage may have contributed to sternal fractures occurring early in the event, at displacement levels below those typically considered injurious, suggesting that fracture risk is not fully described by traditional definitions of chest deformation. The methodology presented here produced novel kinematic data that will be useful in developing biofidelic human models. Additional analysis of the data produced by the reported tests as well as additional tests with a variety of loading conditions are required to fully characterize torso response including ribcage fracture tolerance.

Concept of a platform-based impact isolation system for protection of wheelchair occupants from injuries in vehicle crashes.

To improve the protection of a wheelchair-seated person with disabilities traveling in a vehicle from injuries in a crash, it is proposed to attach the wheelchair to a movable platform separated from the vehicle body by means of a shock isolator. The control of the platform is designed to reduce the occupant's injury risk, as compared with the case of the attachment of the wheelchair directly to the vehicle. The isolator design is based on the minimization of the force transmitted to the wheelchair occupant, provided that the space allowed for the platform to move relative to the vehicle is constrained. The possibility of pre-acting control, when the isolator is engaged for a time prior to the crash, is discussed. Passive tiedown and restraint systems are studied, although it is recognized that active systems could provide even lower injury risks. A multibody model of the platform-based occupied wheelchair is utilized for full-scale simulation of the response of the system to a crash pulse. The simulation shows a noticeable reduction in the injury risk due to the platform and an even greater reduction of injury with pre-acting control.