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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.

To provide effective occupant protection for people who ride in motor vehicles while seated in wheelchairs, products are required that both secure the wheelchair and restrain the occupant. An international effort to develop dynamic test standards for these products has produced a compliance test protocol that includes specification of the sled deceleration-time history, the crash pulse corridor. An interlaboratory study was conducted to determine if the crash pulse corridor was sufficiently defined to produce acceptably low variation in the test results. The study, that involved four labs each replicating the same sled test three times, produced consistent results. The study results suggest that a reasonably precise compliance test protocol can be defined using a crash pulse corridor that is generously drawn to accommodate rather large differences in sled crash pulse shapes.

Rear seat adult occupant protection is receiving increased attention from the automotive safety community. Recent anthropomorphic test device (ATD) studies have suggested that it may be possible to improve kinematics and reduce injuries to rear seat occupants in frontal collisions by incorporating shoulder-belt force-limiting and pretensioning (FL+PT) technologies into rear seat 3-point belt restraints. This study seeks to further investigate the feasibility and potential kinematic benefits of a FL+PT rear seat, 3-point belt restraint system in a series of 48 kmh frontal impact sled tests (20 g, 80 ms sled acceleration pulse) performed with post mortem human surrogates (PMHS). Three PMHS were tested with a 3-point belt restraint with a progressive (two-stage) force limiting and pretensioning retractor in a sled buck representing the rear seat occupant environment of a 2004 mid-sized sedan.

This paper discusses struck-side occupant thoracic response to side-impact loading and the requirements of a sled system capable of reproducing the relevant motions of a laterally impacted vehicle. A simplified viscoelastic representation of a thorax is used to evaluate the effect of the door velocity-time profile on injury criteria and on the internal stress state of the thorax. Simulations using a prescribed door velocity-time profile (punch impact) are contrasted against simulations using a constant-velocity impact (Heidelberg-type impact). It is found that the stress distribution and magnitude within the thorax, in addition to the maximum thorax compression and viscous response, depend not only on the door-occupant closing velocity, but also on the shape of the door velocity-time profile throughout the time of contact with the occupant. A sled system capable of properly reproducing side-impact door and seat motion is described.

The human body undergoes a variety of changes as it ages through adulthood. These include both morphological (structural) changes (e.g., increased thoracic kyphosis) and material changes (e.g., osteoporosis). The purpose of this study is to evaluate structural changes that occur in the aging bony thorax and to assess the importance of these changes relative to the well-established material changes. The study involved two primary components. First, full-thorax computed tomography (CT) scans of 161 patients, age 18 to 89 years, were analyzed to quantify the angle of the ribs in the sagittal plane. A significant association between the angle of the ribs and age was identified, with the ribs becoming more perpendicular to the spine as age increased (0.08 degrees/year, p=0.012). Next, a finite element model of the thorax was used to evaluate the importance of this rib angle change relative to other factors associated with aging.