Assessment of Nanobag as a New Safety System in the Frontal Sled Test

Objective: The future mobility challenges leads to considering new safety systems to protect vehicle passengers in non-standard and complex seating configurations. The objective of this study is to assess the performance of a brand new safety system called nanobag and to compare it to the traditional airbag performance in the frontal sled test scenario. Methods: The nanobag technology is assessed in the frontal crash test scenario and compared with the standard airbag by numerical simulation. The previously identified material model is used to assemble the nanobag numerical model. The paper exploits an existing validated human body model to assess the performance of the nanobag safety system. Using both the new nanobag and the standard airbag, the sled test numerical simulations with the variation of human bodies are performed in 30 km/h and 50 km/h frontal impacts. Results: The sled test results for both the nanobag and the standard airbag based on injury criteria shows a good and acceptable performance of the nanobag safety system compared to the traditional airbag. Conclusion: The results show that the nanobag system has its performance compared to the standard airbag, which means that thanks to the design, the nanobag safety system has a high potential and extended application for multi-directional protection against impact.

Effects of seat pan and pelvis angles on the occupant response in a reclined position during a frontal crash

Current highly automated vehicle concepts include reclined seat layouts that could allow occupants to relax during the drive. The main objective of this study was to investigate the effects of seat pan and pelvis angles on the kinematics and injury risk of a reclined occupant by numerical simulation of a frontal sled test. The occupant, represented by a detailed 50th percentile male human body model, was positioned on a semi-rigid seat. Three seat pan angles (5, 15, and 25 degrees from the horizontal) were used, all with a seatback angle of 40 degrees from the vertical. Three pelvis angles (60, 70, and 80 degrees from the vertical), representing a nominal and two relaxed sitting positions, were used for each seat pan angle. The model was restrained using a pre-inflated airbag and a three-point seatbelt equipped with a pretensioner and a load limiter before being subjected to two frontal crash pulses. Both model kinematic response and predicted injury risk were affected by the seat pan and the pelvis angles in a reclined seatback position. Submarining occurrence and injury risk increased with lower seat pan angle, higher pelvis angle, and acceleration pulse severity. In some cases (in particular for a 15 degrees seat pan), a small variation in seat pan or pelvis angle resulted in large differences in terms of kinematics and predicted injury. This study highlights the potential effects of the seat pan and pelvis angles for reclined occupant protection. These parameters should be assessed experimentally with volunteers to determine which combinations are most likely to be adopted for comfort and with post mortem human surrogates to confirm their significance during impact and to provide data for model validation. The sled and restraint models used in this study are provided under an open-source license to facilitate further comparisons.

Secondary Impact Protection for Locomotive Engineers – Improved Airbag Design

Under the locomotive cab occupant protection research program sponsored by the Federal Railroad Administration (FRA), Sharma & Associates, Inc. (SA) developed a Secondary Impact Protection System (SIPS) for locomotive engineers. The system uses a large, automotive-style, passenger airbag in combination with a deformable knee bolster to provide the level of protection needed for the locomotive engineer, without compromising the normal operating environment and egress. A prior version of the system [1] was prototyped and tested in a dynamic sled test with a 23g crash pulse and was shown to meet most limiting human injury criteria defined in the Department of Transportation (DOT)’s Federal Motor Vehicle Safety Standards (FMVSS 208) [2] for the head, chest, neck, and femur. The system also showed marginal performance for the chest injury index and indicated potential for an improved airbag design to fully meet all requirements. In the current study, simulations with an optimized airbag and higher capacity inflator system showed that SIPS can provide excellent occupant protection for an unbelted locomotive occupant in a frontal crash. Sled testing of SIPS confirmed the performance, and the system successfully met all eleven (11) criteria of the FMVSS 208 standard [2]. The shape and position of the airbag module and its attachments to the desk were generally the same as those presented in previous research. The key changes that helped meet all criteria were the higher capacity inflators, knee bolster system brackets moved forward, thicker knee plate, higher volume airbag and additional vents.

Assessment of Crash Performance of an Automotive Component Made through Additive Manufacturing

The objective of this study was to apply an innovative technique to manufacture a plastic automotive component to reduce its weight and costs, and guarantee its design was safe. A frontal impact sled test was simulated, and the damages to the occupant’s legs were assessed, with specific reference to the dashboard’s glove box. The replacement of the current glove box with a new component fabricated using additive manufacturing was analyzed to evaluate its passive safety performance in the event of an automobile accident. The materials analyzed were polyamide and polypropylene, both reinforced with 5% basalt. The stiffness of the system was previously characterized by reproducing a subsystem test. Subsequently, the same rating test performed by the Euro NCAP (New Car Assessment Program) was reproduced numerically, and the main biomechanical parameters required by the Euro NCAP were estimated for both the current and the additive production of the component.