Head Resultant Acceleration

Description

Head resultant acceleration is the total head-acceleration magnitude across the X, Y, and Z axes [1]. It shows the acceleration intensity without a direction. WebSAT uses this curve to calculate HIC and displays the part of the curve that forms the HIC interval.

This metric does not have a separate button. WebSAT uses resultant head acceleration when you select Injury Metrics > HIC. Head-acceleration data are also used by Vehicle Analysis > NCAP and Component Evaluation > Pedestrian Protection.

Measurements used by WebSAT

• Head Linear Acceleration at Head CG ($a_x$, $a_y$ and $a_z$)

How WebSAT processes the data

1. Use a selected resultant head-acceleration measurement, or calculate the resultant from the selected X-, Y-, and Z-axis measurements:

$$\begin{array}{c}{\displaystyle ResultantHeadAcceleration=}\\ {\displaystyle \sqrt{(a_x{)}^2+(a_y{)}^2+(a_z{)}^2}}\end{array}$$

2. If Apply Filter is selected in the HIC settings, filter the source measurements with the selected filter class before calculating HIC.
3. Convert the resultant curve to g ($1g=9.81m\mathrm{/}{s}^2$).
4. Use the resultant curve to calculate HIC and display the HIC interval.

References

[1] Huang Z., Zhang B., Wang L., Liu C. "Experimental Study on Side Pole Collision and Deformable Barrier Collision of Car". Journal of Physics Conference Series, 2020 June; 1549(3):032120.