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Female occupants sustain high frequency of injury to the foot and ankle in motor vehicle crashes (MVCs). To investigate injury mechanisms, this study evaluated a finite element model of the foot and ankle of a small female occupant (F05). The model was validated in four loading conditions relevant to MVCs (axial rotation,dynamic inversion and eversion, dorsiflexion and axial impact) and scaling approaches were applied to available post-mortem human surrogate data to provide appropriate boundary conditions and experimental biofidelity targets. Compared to an average male model, the F05 model predicted more bony fractures in comparable dynamic loading conditions, consistent with field observations for female occupants in crash incidents. Further research is needed to improve model biofidelity and account for gender and age variations for female occupants. This model will be useful for understanding female-specific injury mechanisms and guiding the development of effective countermeasures in vehicle design. [ABSTRACT FROM AUTHOR]

Objective: The goal of this study was to investigate the influence of the occupant characteristics on seat belt force vs. payout behavior based on experiment data from different configurations in frontal impacts.Methods: The data set reviewed consists of 58 frontal sled tests using several anthropomorphic test devices (ATDs) and postmortem human subjects (PMHS), restrained by different belt systems (standard belt, SB; force-limiting belt, FLB) at 2 impact severities (48 and 29 km/h). The seat belt behavior was characterized in terms of the shoulder belt force vs. belt payout behavior. A univariate linear regression was used to assess the factor significance of the occupant body mass or stature on the peak tension force and gross belt payout.Results: With the SB, the seat belt behavior obtained by the ATDs exhibited similar force slopes regardless of the occupant size and impact severities, whereas those obtained by the PMHS were varied. Under the 48 km/h impact, the peak tension force and gross belt payout obtained by ATDs was highly correlated to the occupant stature (P =.03, P =.02) and body mass (P =.05, P =.04), though no statistical difference with the stature or body mass were noticed for the PMHS (peak force: P =.09, P =.42; gross payout: P =.40, P =.48). With the FLB under the 48 km/h impact, highly linear relationships were noticed between the occupant body mass and the peak tension force (R(2) = 0.9782) and between the gross payout and stature (R(2) = 0.9232) regardless of the occupant types.Conclusions: The analysis indicated that the PMHS characteristics showed a significant influence on the belt response, whereas the belt response obtained with the ATDs was more reproducible. The potential cause included the occupant anthropometry, body mass distribution, and relative motion among body segments specific to the population variance. This study provided a primary data source to understand the biomechanical interaction of the occupant with the restraint system. Further research is necessary to consider these effects in the computational studies and optimized design of the restraint system in a more realistic manner. [ABSTRACT FROM AUTHOR]

Far side has been identified in the literature as a potential cause of numerous injuries and fatalities. Euro NCAP developed a far side test protocol to be performed to assess adult protection. A monitoring phase was undertaken between January 2018 and December 2019, and the far side assessment will become part of the rating for all vehicles launched in 2020 onward. A test buck was developed and 6 paired WorldSID / Post Mortem Human Subjects (PMHS) were subjected to the test protocol proposed by Euro NCAP to contribute to the development of limits. The buck consisted of a rigid seat and a rigid central console covered with 50 mm of Ethafoam TM 180 with a density of 16 kg/m3. The buck was mounted on the sled with an angle of 75° between the X axis of the vehicle and the X axis of the sled. The peak head excursion was compared between PMHS and the WorldSID dummy. It was found reasonably similar. However, the dummy repeatability was found to be poor. Out of 6 tests conducted on 6 PMHS, 2 specimens sustained AIS3 and, 3 specimens AIS2 cervical spine injuries, 3 specimens sustained AIS3, 1 AIS2 and 1 AIS1 thoracic injuries, and 2 specimens sustained AIS2 abdominal injuries. The peak values recorded on the dummy according to the Euro NCAP protocol were compared with the injury assessments of the PMHS tests. In the configuration used, which includes a central console, the hard thorax injury prediction was found to be excellent. For the neck injury prediction, the data were merged with similar results available in the literature and an Injury Risk Curve was proposed as a derivative from the curve published by Mertz et al. (2003) for neck extension.

The objective of the study was to analyze independently the contribution of pre-impact spine posture on impact response by subjecting a finite element human body model (HBM) to whole-body, lateral impacts. Seven postured models were created from the original HBM: one matching the standard driving posture and six matching pre-impact posture measured for each of six subjects tested in previously published experiments. The same measurements as those obtained during the experiments were calculated from the simulations, and biofidelity metrics based on signals correlation were established to compare the response of HBM to that of the cadavers. HBM responses showed good correlation with the subject response for the reaction forces, the rib strain (correlation score=0.8) and the overall kinematics. The pre-impact posture was found to greatly alter the reaction forces, deflections and the strain time histories mainly in terms of time delay. By modifying only the posture of HBM, the variability in the impact response was found to be equivalent to that observed in the experiments performed with cadavers with different anthropometries. The patterns observed in the responses of the postured HBM indicate that the inclination of the spine in the frontal plane plays a major role. The postured HBM sustained from 2 to 5 bone fractures, including the scapula in some cases, confirming that the pre-impact posture influences the injury outcome predicted by the simulation.

Thoracic injuries are a major cause of mortality in frontal collisions, especially for elderly female and obese people. Car occupant individual characteristics like age, gender and Body Mass Index (BMI) are known to influence human vulnerability tolerance in crashes. The objective of the this study was to perform in vivo test experiments to quantify the influence of subject characteristics in terms of age, gender and anthropometry and on thorax mechanical response variability under belt loading. Thirty-nine relaxed volunteers of different anthropometries, genders and age were submitted to non-injurious sled tests (4 g, 8 km/h) with a sled buck representing the environment of a front passenger restrained by a 3-point belt. A resulting shoulder belt force FRes was computed using the external and internal shoulder belt loads and considering shoulder belt geometry. The mid sternal deflection D was calculated as the distance variation between markers placed at mid-sternum and at the 7th vertebra spinous process of the subject. Linear stiffness (K) and damping coefficient (μ) of a spring-dashpot model were identified from the FRes-D curves of each test. The analysis suggests that among subjects over 40 years old, thinness leads to higher K-values.