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Two new algorithms for frontal crash discrimination were proposed; one used the deceleration change multiplied by the velocity change as a metric, and the other used the deceleration squared multiplied by the velocity change. For all the frontal crash modes studied in this paper, the first algorithm resulted in the time-to-fires of frontal air bags less than the required time-to-fires, and the second algorithm resulted in the time-to-fires less than the required time-to-fires except only for underride crashes. Moreover, it was proposed that an accelerometer be installed at each side of the rails, rockers or pillars to assess the crash severity of each side especially during an asymmetric crash such as oblique and offset crashes. As an example, the deceleration pulses measured at the left and right B-pillar · rocker locations were processed through the first algorithm, and appropriate but different time-to-fires of the driver air bag and the passenger air bag were obtained.

This paper describes the steps and procedures involved in the development, calibration, and validation of a finite element model of a deformable featureless headform (Hybrid III head without nose). Development efforts included: a headform scan to verify geometric accuracy, quantification of general-purpose construction of the finite element model from the scanned data, viscoelastic parameters for the constitutive model definition of the headform skin, and models of drop tests with impact speeds of 9.775, 14.484, 19.312, and 24.140 km/h (6.074, 9, 12, and 15 mph). The predictions of all pertinent headform responses during the calibration were in excellent agreement with related experiments. The validity of the headform model and the headform impact methodology were verified in both component and full vehicle environments. This was accomplished through comparisons of finite element simulations with tests of the headform responses at 24.140 km/h (15 mph) impact.