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The present study describes the development of a refined finite element model of the human pelvis. The objectives of this research work were to: Statistically study the human pelvis geometry, and develop a parameterized model. Mechanically validate the model with regard to the available in-house experimental data. Model the injury mechanisms observed in the experimental studies. The significant dimensions of the pelvis were identified by statistical analysis of the pelvis geometry based on the Reynolds et al. data [1]. Those dimensions were used to classify the in-house tested pelves. An interpolation technique (Kriging [2, 3, 4, 5, 6, 7 and 8]) was then used in order to distort a reference mesh and adapt its geometry to the measured geometry of the tested pelvis. The mechanical validation of the model was carried out by comparing numerical and experimental results, and the influence of the geometrical variations on the behavior of the pelvis was thus assessed.

This paper presents an analysis of the displacement measurement of the Hybrid III 50th percentile male dummy chest in quasistatic and dynamic loading environments. In this dummy, the sternal chest deformation is typically characterized using a sliding chest potentiometer, originally designed to measure inward deflection in the central axis of the dummy chest. Loading environments that include other modes of deformation, such as lateral translations or rotations, can create a displacement vector that is not aligned with this sensitive axis. To demonstrate this, the dummy chest was loaded quasistatically and dynamically in a series of tests. A string potentiometer array, with the capability to monitor additional deflection modes, was used to supplement the measurement of the chest slider.

Current crash dummy biofidelity standards include the estimated effects of tensing the muscles of the thorax. This study reviewed the decision to incorporate muscle tensing by examining relevant past studies and by using an existing mathematical model of thoracic impacts. The study finds evidence that muscle tensing effects are less pronounced than implied by the biofidelity standard response corridors, that the response corridors were improperly modified to include tensing effects, and that tensing of other body regions, such as extremity bracing, may have a much greater effect on the response and injury potential than tensing of only the thoracic musculature. Based on these findings, it is recommended that muscle tensing should be eliminated from thoracic biofidelity requirements until there is sufficient information regarding multi-region muscle tensing response and the capability to incorporate this new data into a crash dummy.

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.

The abdomen is the second most commonly injured region in children using adult seat belts, but engineers are limited in their efforts to design systems that mitigate these injuries since no current pediatric dummy has the capability to quantify injury risk from loading to the abdomen. This paper develops a porcine (sus scrofa domestica) model of the 6-year-old human's abdomen, and then defines the biomechanical response of this abdominal model. First, a detailed abdominal necropsy study was undertaken, which involved collecting a series of anthropometric measurements and organ masses on 25 swine, ranging in age from 14 to 429 days (4-101 kg mass). These were then compared to the corresponding human quantities to identify the best porcine representation of a 6-year-old human's abdomen. This was determined to be a pig of age 77 days, and whole-body mass of 21.4 kg.

Very little experimental research has focused on the kinematics, dynamics, and injuries of rear-seated occupants. This study seeks to develop a baseline response for rear-seated post mortem human surrogates (PMHS) in frontal crashes. Three PMHS sled tests were performed in a sled buck designed to represent the interior rear-seat compartment of a contemporary midsized sedan. All occupants were positioned in the right-rear passenger seat and subjected to simulated frontal crashes with an impact speed of 48 km/h. The subjects were restrained by a standard, rear seat, 3-point seat belt. The response of each subject was evaluated in terms of whole-body kinematics, dynamics, and injury. All the PMHS experienced excessive forward translation of the pelvis resulting in a backward rotation of the torso at the time of maximum forward excursion.

Recent field data studies have shown that force-limiting belt systems reduce the occurrence of thoracic injuries in frontal crashes relative to standard (not force-limiting) belt systems. Laboratory cadaver tests have also shown reductions in trauma, as well as in chest deflection, associated with a force-limiting belt. On the other hand, tests using anthropomorphic test devices (ATDs) have shown trends indicating increased, decreased, or unchanged chest deflection. This paper attempts to resolve previous experimental studies by comparing the anterior-posterior and lateral chest deflections measured by the THOR and Hybrid III (H-III) dummies over a range of experimental conditions. The analysis involves nineteen 48-km/h and 57-km/h sled tests utilizing force-limiting and standard seat belt systems, both with an air bag. Tests on both the driver side and the passenger side are considered.

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.

Thoracic trauma is the principle causative factor in 30% of road traffic deaths. Researchers have developed force-deflection corridors of the thorax for various loading conditions in order to elucidate injury mechanisms and to validate the mechanical response of ATDs and numerical human models. A corridor, rather than a single response characteristic, results from the variability inherent in biological experimentation. This response variability is caused by both intrinsic and extrinsic factors. The intrinsic factors are associated with individual differences among human subjects, e.g., the differences in material properties and in body geometry. The extrinsic sources of variability include fluctuations in the loading and supporting conditions in experimental tests.