Feasibility study of a safe sled environment for reclined frontal deceleration tests with human volunteers

Abstract

Objective: The goal of the study was to assess the feasibility of a safe crash environment for volunteer tests in reclined seating positions. An iterative multimodal approach was chosen, consisting of full-body human body model (HBM) simulations, anthropomorphic test device (ATD) physical testing, and volunteer testing.

Methods: To estimate a noninjurious deceleration pulse, the iterative inclination of the seat was supported through HBM simulations and physical ATD testing. One male volunteer was exposed to 5 low-speed frontal sled impacts with stepwise reclined seat angles. The volunteer was restrained with a non-pretensioned 3-point seat belt. All procedures were approved by the relevant ethics boards.

Results: Volunteer sled tests in 3 different seat configurations were performed with one volunteer at noninjurious deceleration levels. Inclination of the seat and the absence of a footrest resulted in elevated axial seat reaction forces and almost pure translational motion of the human body.

Conclusions: A maximum speed of 7.1 km/h and peak deceleration of 3.0 g was found to be a safe pulse for volunteer testing in frontal impacts with a rigid reclined seat. Larger soft tissue deformations were observed when reclined, possibly associated with higher shear loads within the soft tissue. Preliminary results highlight trade-offs between the degree of seat angulation, friction force, and restraint capability of a 3-point seat belt, thus causing forward translation and/or axial spinal compression of the occupant that may need to be addressed in the future.

Keywords:

• Human volunteer testing
• noninjurious sled pulse
• frontal impact
• reclined seating posture
• kinematics
• restraint system

Acknowledgments

The authors express their deepest gratitude to the volunteer for making this study possible.

Additional information

Funding

Parts of the tests included in this study received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement no. 636136.