FMVSS 208 neck loads (208Neck)

Description

208Neck evaluates an individual neck force or bending-moment channel against the available ATD-specific assessment reference values. Unlike Nij, it reports axial, shear, and bending responses separately [1] [2].

When this feature is available

208Neck becomes available when either the current curve selection or any loaded test contains a neck measurement set that meets the requirements. Only channels with a usable data status count.

The required measurement set includes:

• The signal attachment must be NECK - UPPER or NECK - LOWER.
• The group must contain at least one of the following channels:
  • Axis: X - LOCAL, Units: NEWTONS for forward/rearward shear
  • Axis: Z - LOCAL, Units: NEWTONS for tension/compression
  • Axis: Y - LOCAL, Units: NEWTON-METERS for flexion/extension

WebSAT checks each occupant and neck location independently and enables 208Neck if any eligible measurement set contains at least one supported load channel. A group can produce a partial result when only some load types are present.

Settings

This feature has no settings.

How WebSAT processes the data

1. Identify each supported neck-force or neck-moment channel in the qualifying measurement set.
2. Convert the channels to standard force or moment units.
3. Determine the load type and direction from the axis, units, and signal polarity.
4. Apply the appropriate impact-test filtering.
5. Find the positive and negative peaks for every available load type.
6. Attach the available ATD-specific critical value to each result.
7. Report the available shear, axial-force, and bending-moment results for the occupant and neck location.

Reference values and injury risk

The current 208Neck calculation uses the upper-neck fields shown below. Axial force uses the upper-neck tension and compression limits, shear uses the upper-neck shear limit in both directions, and bending moment uses the upper-neck Nij flexion and extension critical intercepts. The values follow the FMVSS 208 and published ATD injury-assessment definitions [1] [2]. A dash means the selected ATD does not provide that reference value, so WebSAT reports the peak without a percent-of-reference comparison for that direction.

ATD	Tension (N)	Compression (N)	Shear, ± (N)	Flexion intercept (N·m)	Extension intercept (N·m)
Hybrid III 95th male	5030	-4830	3740	405	-177
Hybrid III 50th male	4170	-4000	3100	310	-135
Hybrid III 5th female	2620	-2520	1950	155	-67
Hybrid III 10-year-old	2290	-2200	1710	125	-54.8
Hybrid III 6-year-old	1490	-1820	1410	96	-42
Hybrid III 3-year-old	1130	-1380	1070	67	-29.3
CRABI 18-month	1080	-1040	810	46.8	-20.4
CRABI 12-month	990	-960	740	42.5	-18.6
CRABI 6-month	930	-890	690	39.5	-17.3
THOR 50th male	—	—	—	60	-79.2
THOR 5th female	4170	-4000	—	88.1	-117
SID-IIs 5th female	2620	-2520	1950	153	-66.9
BioSID 50th male	—	—	3100	—	—

These are the values WebSAT places beside the positive and negative result peaks. The function does not combine the loads or convert them into an AIS probability; use Nij when a combined axial-force/bending-moment assessment is required.

Results

208Neck summary for the upper- and lower-neck measurements from the left- and right-front-seat occupants in test 10099.

Upper-neck axial force used to identify the tension and compression peaks.

Upper-neck shear force used for the forward and rearward peak checks.

Corrected bending moment used for the flexion and extension checks.

References

[1] National Highway Traffic Safety Administration. “Federal Motor Vehicle Safety Standards; Occupant Crash Protection; Final Rule.” Federal Register, 65(208), 2000, pp. 67691–67703.

[2] Mertz, H. J., Irwin, A. L., and Prasad, P. “Biomechanical and Scaling Bases for Frontal and Side Impact Injury Assessment Reference Values.” Stapp Car Crash Journal, 47, 2003, pp. 155–188. SAE Technical Paper 2003-22-0009.