Boggess, 1 MASS-BASED CONSIDERATIONS FOR HEAD INJURY PROTECTION DEVELOPMENT

The purpose of this research study is to understand the mass limits of typical instrument panel (IP) components given standard design guidelines for head injury risk reduction. The IP components of passenger vehicles are continually changing to increase features and quality. Consequently, these changes increase the mass of the IP components. It was hypothesized that, regardless of the mounting, certain IP components possess significant inertial resistance such that injury risk values may be above accepted risk levels without modification to their internal structures. Using the FMVSS201 test procedure, multiple IP components from several vehicles (n=6) were tested for head injury risk both in-vehicle and as isolated suspended systems. The isolated components were tested using a simple pendulum setup with the component properly oriented and suspended from 2m cables. The component then was impacted with a 6.8kg linear head impactor at a velocity of 19.0km/h. Initial results showed that in an isolated state, the injury values, both peak and 3ms clip deceleration, correspond to as much as 93 % of the in-vehicle tested values. From the component and in-vehicle tests, work functions based on the component mass were developed to replicate the impact event and establish mass-based thresholds. Models studied included waveforms comprised of haversine, half-sine, triangular, trapezoidal and square functions. A simple spring-mass model was also used to characterize the impact event. Initial assessment of the model showed the energy associated with an impact to a typical 4.5kg tuner assembly is great enough to potentially exceed the acceptable injury risk values according to Federal regulations. Furthermore, integrated structures such as air bag modules have a lower mass threshold due to their internal stiffness and interaction with the IP. Based on these thresholds, some design guidelines to improve the crush characteristics of structures such as tuners, HVAC controllers, and air bag modules are presented