THIS 22.1
Tibia Index (TI)
Tibia Index (TI) is commonly used to predict lower leg injury. T/HIS calculates the Tibia Index based on the following interaction formula specified in Euro NCAP Technical Bulletin (TB021) v4.1.
where:
| \(M_R(t)\) | = Filtered resultant Tibia Moment |
|---|---|
| \(M_x(t)\) | = Filtered lateral Tibia Moment |
| \(M_y(t)\) | = Filtered Fore Tibia Moment |
| \(F_z(t)\) | = Filtered Axial Tibia Force |
| \((M_R)_C\) | = Moment critical value |
| \((F_z)_C\) | = Force critical value |
According to Euro NCAP Technical Bulletin (TB021) v4.1, the Axial and Moment curves must be filtered using CFC 600 filter. If you provide unfiltered input curves, you can use the auto-filtering option available in the Tibia Index menu. When auto-filtering is turned ON, T/HIS will first filter the input curves using the selected filter class and then perform the Tibia Index calculation with the filtered curves.
The TI critical values for different standard types of Occupants are:
| Occupant type | \((M_R)_C\) [Nm] | \((F_z)_C\) [kN] |
|---|---|---|
| HIII-95M | 307 | 44.2 |
| HIII-50M | 225 | 35.9 |
| HIII-05F | 115 | 22.9 |
| THOR | 225 | 35.9 |