Evaluation of the thoracic deflection measurement system

Eggers, Andre; Adolph, Thorsten

Affiliations

¹Federal Highway Research Institute, BASt, Germany

Abstract

Thoracic injury is one of the predominant types of severe injuries in frontal accidents. The assessment of the injury risk to the thorax in the current frontal impact test procedures is based on the uni-axial chest deflection measured in the dummy Hybrid III. Several studies have shown that criteria based on the linear chest potentiometer are not sensitive enough to distinguish between different restraint systems, and cannot indicate asymmetric chest loading, which has been shown to correlate to increased injury risk. Furthermore, the measurement is sensitive to belt position on the dummy chest. The objective of this study was to evaluate the optical multipoint chest deflection measurement system ‘RibEye’ in frontal impact sled tests. Therefore the sensitivity of the RibEye system to different restraint system parameters was investigated. Furthermore, the issue of signal drop out at the 6th rib was investigated in this study.A series of sled tests were conducted with the RibEye system in the Hybrid III 50%. The sled environment consisted of a rigid seat and a standard production three-point seat belt system.

Rib deflections were recorded with the RibEye system and additionally with the standard chest potentiometer. The tests were carried out at crash pulses of two different velocities (30 km/h and 64 km/h).

The tests were conducted with different belt routing to investigate the sensitivity of chest deflection measurements to belt position on the dummy chest. Furthermore, different restraint system parameters were investigated (force limiter level, with or without pretensioning) to evaluate if the RibEye measurements provide additional information to distinguish between restraint system configurations. The results showed that with the RibEye system it was possible to identify the effect of belt routing in more detail.

The chest deflections measured with the standard chest potentiometer as well as the maximum deflection measured by RibEye allowed the distinction to be made between different force limiter levels.

The RibEye system was also able to clearly show the asymmetric deflection of the rib cage due to belt loading. In some configurations, differences of more than 15 mm were observed between the left and side areas of the chest. Furthermore, the abdomen insert was identified as source of the problem of signal drop out at the 6th rib. Possible solutions are discussed.

In conclusion, the RibEye system provided valuable additional information regarding the assessment of restraint systems. It has the potential to enable the evaluation of thoracic injury risk due to asymmetric loading.

Further investigations with the RibEye should be extended to tests in a vehicle environment, which include a vehicle seat and other restraint system components such as an airbag.

Links

URL: http://www-nrd.nhtsa.dot.gov/pdf/esv/esv22/22ESV-000190.pdf

Cited Works (7)

Year	Entry
2003	Kent R, Lessley D, Shaw G, Crandall J. The utility of Hybrid III and THOR chest deflection for discriminating between standard and force-limiting belt systems. Stapp Car Crash J. 2003;47:267-297. SAE 2003-22-0013.
2010	Carroll J, Adolph T, Chauvel C, Labrousse M, Trosseille X, Pastor C, Eggers A, Smith S, Hynd D. Overview of serious thorax injuries in european frontal car crash accidents and implications for crash test dummy development. In: Proceedings of the 2010 International IRCOBI Conference on the Biomechanics of Impact. September 15-17, 2010; Hannover, Germany.217-234.
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2009	Yoganandan N, Pintar FA. Evaluation of the ribeye deflection measurement system. In: Proceedings of the 21st International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 15-18, 2009; Stuttgart, Germany.
2003	Petitjean A, Baudrit P, Trosseille X. Thoracic injury criterion for frontal crash applicable to all restraint systems. Stapp Car Crash J. 2003;47:323-348. SAE 2003-22-0015.
2002	Petitjean A, Lebarbe M, Potier P, Trosseille X, Lassau J-P. Laboratory reconstructions of real world frontal crash configurations using the Hybrid III and THOR dummies and PMHS. Stapp Car Crash J. 2002;46:27-54. SAE 2002-22-0002.

Cited By (2)

Year	Entry
2014	Eggers A, Eickhoff B, Dobberstein J, Zellmer H, Adolph T. Effects of variations in belt geometry, double pretensioning and adaptive load limiting on advanced chest measurements of THOR and Hybrid III. In: Proceedings of the 2014 International IRCOBI Conference on the Biomechanics of Injury. September 10-12, 2014; Berlin, Germany.347-358.
2022	Edwards MA, Jagtap SR, Jermakian JS. Sensitivity of established and alternative rear occupant thoracic injury metrics to seat belt design variables in frontal impacts. In: Proceedings of the 2022 International IRCOBI Conference on the Biomechanics of Injury. September 14-16, 2022; Porto, Portugal.747-770.