Neck Lateral Moment
Overview
Neck lateral moment represents the rotational force around the x-axis of the neck, causing the head to rotate to the left or right (see figure below) [1]. This type of loading can result in neck strain, soft tissue damage, or injury to the vertebral discs [1]. If the ATD used in testing has an established Injury Assessment Reference Value (IARV), the peak lateral moment is reported as a percentage of that IARV to indicate potential injury severity [2].
Required Signals
- Moment of the Upper or Lower Neck (X)
Calculation
- The neck lateral moment (force at the x-axis) is converted to newton meters (Nm) (only applicable if values aren't already in Nm)
- The neck lateral moment is filtered at CFC = 600
- Signal is truncated to start at 0 seconds (only applicable if signal has moment values before time = 0 seconds)
- Finds the absolute maximum lateral moment and the time it occured
- Calculates the percent of the IARV that the absolute maximum neck lateral force reaches
Neck Lateral Moment IARV Table [3]
| ATD | IARV - in position tests (Nmm) | IARV - out of position tests (Nmm) |
|---|---|---|
| CRABI – 6mo | 19 | 18 |
| CRABI – 12mo | 21 | 19 |
| CRABI – 18mo | 21 | 21 |
| HIII – 3yo | 32 | 30 |
| HIII – 6yo | 45 | 42 |
| HIII – 10yo | 59 | 55 |
| HIII – F05 | 72 | 67 |
| HIII – M50 | 144 | 134 |
| HIII – M95 | 190 | 178 |
| BioSID | 144 | 134 |
In position testing refers to crash testing where the ATD is properly seated and restrained, similar to a typical driving scenario [4]. Out of position testing refers to crash testing where the ATD may be in a non-seated posture or have shifted from their seat [4].
References
[1] Yoganandan N, Humm J, Pintar FA, Wolfla CE, Maiman DJ. Lateral neck injury assessments in side impact using post mortem human subject tests. Ann Adv Automot Med. 2011;55:169-79.
[2] "Frontal Offset Crashworthiness Evaluation". Guidelines for Rating Injury Measures, Insurance Institue for Highway Safety, June 2009.
[3] Yoganandan, Narayan, et al. "Accidental Injury". Biomechanics and Prevention, 3rd edition. Springer, 2020.
[4] "Guidlines for Using the UMTRI ATD Positioning for ATD and Seat Positioning (Version I)". Insurance Institute for Highway Safety, January 2003.