Head injury criterion

The Head Injury Criterion (HIC) is a measure of the likelihood of head injury arising from an impact. The HIC can be used to assess safety related to vehicles, personal protective gear, and sport equipment. The Head Injury Criterion (HIC) is a measure of the likelihood of head injury arising from an impact. The HIC can be used to assess safety related to vehicles, personal protective gear, and sport equipment. Normally the variable is derived from the measurements of an accelerometer mounted at the center of mass of a crash test dummy’s head, when the dummy is exposed to crash forces. It is defined as: H I C = max t 1 , t 2 { [ 1 t 2 − t 1 ∫ t 1 t 2 a ( t ) d t ] 2.5 ( t 2 − t 1 ) } {displaystyle {mathit {H}}{mathit {I}}{mathit {C}}=max _{t_{1},t_{2}}{igg {}{Big }^{2.5}left(t_{2}-t_{1} ight){igg }}} where t1 and t2 are the initial and final times (in seconds) chosen to maximize HIC, and acceleration a is measured in gs (standard gravity acceleration). The time duration, t2 – t1, is limited to a maximum value of 36 ms, usually 15 ms.