Modeling Occupants in Far-Side Impacts

Abstract

Far-side impacts are not part of any regulated NCAP, FMVSS, or similar test regime despite accounting for 43 percent of the seriously injured persons and 30 percent of the harm in U.S. side impact crashes. Furthermore, injuries to the head and thorax account for over half of the serious injuries sustained by occupants in far-side crashes. Despite this, there is no regulated or well-accepted anthropomorphic test device (ATD) or computer model available to investigate far-side impacts. As such, this presents an opportunity to assess a computer model that can be used to measure the effect of varying restraint parameters on occupant biomechanics in far-side impacts.

Objective: This study sets out to demonstrate the modified TASS human facet model's (MOTHMO) capabilities in modeling whole-body response in far-side impacts.

Method: MOTHMO's dynamic response was compared to that of postmortem human subjects (PMHS), WorldSID, and Thor-NT in a series of far-side sled tests. The advantages, disadvantages, and differences of using MOTHMO compared to ATDs were highlighted and described in terms of model design and instrumentation. Potential applications and improvements for MOTHMO were also recommended.

Results: The results showed that MOTHMO is capable of replicating the seat belt–to-shoulder complex interaction, pelvis impacts, head displacement, neck and shoulder belt loading from inboard mounted belts, and impacts from multiple directions. Overall, the model performed better than Thor-NT and at least as well as WorldSID when compared to PMHS results. Though WorldSID and Thor-NT ATDs were capable of reproducing many of these impact loads, measuring the seat belt–to-shoulder complex interaction and thoracic deflection at multiple sites and directions was less accurately handled.

Conclusion: This study demonstrated that MOTHMO is capable of modeling whole-body response in far-side impacts. Furthermore, MOTHMO can be used as a virtual design tool to explore the effect of varying restraint parameters on occupant kinematics in far-side crash configurations.

Keywords:

• Far side
• Human model
• Side impact
• Seat belt

ACKNOWLEDGMENTS

The funding for this study was provided in part by the Australian Research Council with cost sharing and support from other sponsors, including GM Holden Innovation and Autoliv Research. Additional funding for this research was provided by private parties, who have selected Dr. Kennerly Digges (and the FHWA/NHTSA National Crash Analysis Center at the George Washington University) to be an independent solicitor of and funder for research in motor vehicle safety and to be one of the peer reviewers for the research projects and reports. Neither of the private parties have determined the allocation of funds or had any influence on the content. The authors also thank Frank Pintar and Narayan Yoganandan of Neuroscience Research Laboratories at the VA Medical Center in Milwaukee, Wisconsin, for the use of their PMHS and ATD test data.