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Citation
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Hollowell WT, Reichert R, Park CK. 27th International Technical Conference on the Enhanced Safety of Vehicles (ESV); April 3-6, 2023; Abstract #: 23-0251, pp. 24p. Washington, DC USA: US National Highway Traffic Safety Administration, 2023 open access. |
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Abstract
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27th International Technical Conference on the Enhanced Safety of Vehicles (ESV): Enhanced and Equitable Vehicle Safety for All: Toward the Next 50 Years
https://www-esv.nhtsa.dot.gov/Proceedings/27/27ESV-000251.pdf
Research Question/Objective: New vehicle concepts of occupied and un-occupied Automated Driving Systems [(U)ADS] are fast evolving. Their design, materials used, and energy absorbing structures can significantly differ from traditional vehicles. Appropriate analysis methods and safety metrics can help to evaluate their crashworthiness and compatibility when colliding with other vehicles or road-side hardware. This paper explores the effect different material concepts of an ADS vehicle's outer body has on self-protection and partner protection. The research is considered an example to demonstrate how various impact configurations and simulation analysis tools and metrics can be used to assess structural and occupant aspects for this new type of vehicle class. Methods and Data Sources: Previously developed Finite Element (FE) models of generic ADS vehicles in combination with validated road-side hardware, crash barrier, and occupants were used to understand the effect different material concepts can have on self- and partner-protection. Partner-protection was analyzed using EuroNCAP's mobile progressive deformable barrier (MPDB) and its respective compatibility metric Occupant Load Criterion (OLC), where lower values represent better compatibility. Self-protection was studied using occupant injury metrics recorded during a run-off road impact scenario, where the ADS vehicles impacted a New Jersey Barrier (NJB). Results: Differences in crash compatibility were observed depending on the material concepts used. The impact of a mid-size ADS vehicle using thermoplastic material for select components with the MPDB resulted in an OLC value of 18. The same vehicle with a composite material concept showed an OLC value of 19, while an OLC value of 22 was recorded for the baseline vehicle with a steel material concept. Differences in occupant metrics HIC, BRIC, chest deflection, and femur loads were small when comparing the three material concepts in a 35-mph oblique impact into a NJB. Discussion and Limitations: The use of different material concepts resulted in different total vehicle mass. The vehicle using thermoplastic material for select components had a mass of 3,653 kg. The same vehicle with composite material concept had a mass of 3,718 kg, while the baseline vehicle using steel had a mass of 4,273 kg. Lower vehicle mass correlated with better partner-protection based on OLC metrics. Occupant metrics were mainly affected by the interior concept, which was identical for all three vehicles. Differences in occupant load was therefore small. The same vehicle design and underlying structure was used during this study and no optimization towards the respective material concept was performed. Conclusions and Relevance to Session Submitted: The research is relevant to demonstrate how simulation tools can contribute to assessing this new type of ADS vehicle class. Material concepts that resulted in a smaller vehicle mass tended to show better partner protection. The interior concept, which was the same for all three ADS vehicle variations, was the main factor for producing similar occupant injury metrics for the evaluated impact scenario.
Language: en |