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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.

This study investigates the technique used and forces applied on the latch plate and buckle during typical seat belt operation and driving conditions. These techniques and forces are relevant to whether the latch plate can be partially engaged with the buckle during typical operation and whether the latch plate will dislodge during vehicle operation. In addition to studying the insertion of the latch plate, we examined the tensile forces that are applied to the latch plate and buckle during typical, non-crash driving conditions, and how these forces compare to the performance requirements established by the National Highway Traffic Safety Administration (NHTSA) as part of Federal Motor Vehicle Safety Standards (FMVSS) 209. These tensile forces are important in understanding whether the latch plate is likely to dislodge from the buckle if it is in a position of partial engagement.

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.

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.

The correct restraint for children, age 4-10 years, is a booster seat restrained by the vehicle's seat belt system. The goal of this study is to investigate the effects of misuse of the restraint system by varying initial seat belt slack and to investigate the effects of modern countermeasures, like force limiting belts and pretensioners, on the injury risk of young children. A multi-body model of a Hybrid III 6-year old dummy positioned in a booster seat and restrained by the car seat belt was developed using MADYMO and validated using sled tests. As anticipated, adding initial slack resulted in higher peak accelerations and to an increase in forces and moments in the neck, both factors increasing the injury risk significantly. The countermeasures pretensioning and force limiting prove to be useful in lowering peak values but a high risk of injury persists. A combination of pretension and force limiting provides the safest restraint for this setup.

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.

A substantial percentage of serious and fatal injuries sustained by motor vehicle occupants occur in lateral impact collisions, and approximately one third of these injuries involve a far-side occupant. A center airbag, deploying inboard of the front seat occupants, has been integrated into certain vehicles to reduce far-side occupant excursion, to limit occupant interactions with the vehicle interior and/or another occupant, and to reduce occupant loading and injury potential. A series of sled tests was conducted to better understand the efficacy and limitations of a center airbag under a variety of high-speed lateral impact conditions in an environment outside of the production design. A production-level driver’s seat equipped with a seat-mounted center airbag was installed onto an open-air sled. A 50th percentile male SID H-3 was placed in the seat and restrained by a three-point seat belt equipped with retractor and buckle pretensioners.

Field accident data and vehicle crash and sled testing indicate that occupant kinematics, loading, and associated injury risk generally increase with crash severity. Further, these data demonstrate that the use of restraints, such as three-point belts, provides mitigation of kinematics and reduction in loading and injury potential. This study evaluated the role of seat belts in controlling occupant kinematics and reducing occupant loading in moderate severity frontal collisions. Frontal tests with belted and unbelted anthropomorphic test devices (ATDs) in the driver and right front passenger seats were performed at velocity changes (delta-Vs) of approximately 19 kph (12 mph) and 32 kph (20 mph) without airbag deployment. At the lower-moderate severity (19 kph), motion of the belted ATDs was primarily arrested by seat belt engagement, while motion of the unbelted ATDs was primarily arrested by interaction with forward vehicle structures.

Decades after their introduction, seat belts remain the most important safety innovation in automotive history. Seat belt usage remains the single most effective way to minimize the risk of injury or death in severe crash events. Despite having matured, seat belts continue to evolve and improve and are expected to play an equally critical role in future passenger vehicles as increasing automation leads to changes in occupant compartment design and occupant-to-vehicle interaction. In this paper, an overview of major technical milestones in the development of seat belts is presented, ranging from the earliest lap belts to today’s systems that seamlessly synthesize and integrate information from a variety of sensors to prepare the restraints for an imminent crash. A brief overview of contemporary regulatory events is also provided, illustrating how regulatory actions have followed and occasionally driven the development and proliferation of various aspects of occupant restraints.

Low-speed sideswipe collisions between tractor-semitrailers and passenger vehicles may result in large areas of visible damage to the passenger vehicle. However, due to the extended contact that occurs during these impacts, it is typical in these incidents for the crash pulse duration to be long and the vehicle accelerations to be correspondingly low. Research regarding the impact environment and resulting injury potential of the occupants during these types of impacts is limited. Five full-scale crash tests utilizing a tractor-semitrailer and a passenger car were conducted to explore the occupant responses during these types of collisions. The test vehicles included a van semitrailer pulled by a tractor and three identical mid-sized sedans. The occupants of the sedans included an instrumented Hybrid III 5th -percentile-male anthropomorphic test device (ATD) in the driver's seat and an un-instrumented Hybrid III 5th -percentile-female ATD in the left rear seat.