Evaluation of Dynamic Spit Tester using Computational Biomechanics for Occupant Ejection Mitigation Research

C.K. Thorbole, S.A. Batzer, and D.A. Renfroe (USA)


Biomechanics, Computational, Modelling, MADYMO, LS-DYNA, Crashworthiness


When developing an ejection mitigation system for passenger vehicles, it is necessary to quantify the loads exerted by unconstrained occupants on glazing (window). Quantifying loads on vehicle interior components, such as the door and glazing are important to developing occupant protection systems. Loads exerted by unconstrained occupants on glazing can result in failure leading to fatal ejection. The determination of loads exerted by unconstrained occupants when conducted in dolly rollover (FMVSS 208) or physical highway-speed rollover tests using ATDs (Anthropomorphic Test Dummies) is costly, time consuming, and non repeatable. These limitations make the laboratory dynamic spit test a good candidate to quantify the loads on the glazing and door. However, the spit tester constrains the vehicle, leading to an overestimation of the load on the glazing and door. The results of this current investigation detail the inherent overestimation by the laboratory spit tester and provide a correction factor for a particular vehicle/occupant combination. By using a computational model, the correlation between the spit test result and the actual unconstrained phase of the rollover is provided.

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