Upper Neck Load Cell

Overview

According to SAE J1733, the Upper Neck Load Cell is a transducer used in crash test dummies to measure forces and moments at the occipital condyle, helping assess neck injury risk [1]. It captures axial loads (tension/compression), shear forces, and bending moments, with standardized sign conventions to ensure consistent data across tests [1]. These measurements are essential for calculating injury metrics like Nij and evaluating restraint system performance in regulatory tests such as FMVSS 208 [2].

Calculation

The below information is taken from SAE 1733 [1].

$$\tag{Equation 1} M_{O.C, x} = M_x + F_y (O.D.)$$ $$\tag{Equation 2} M_{O.C, y} = M_y - F_x (O.D.)$$

$M_{O.C. ,x}$ = Moment x about the occipital condyle, $M_{O.C. ,y}$ = Moment y about the occipital condyle, $M_x$ = Moment x measured by the load cell, $M_y$ = Moment y measured by the load cell.

Upper Neck Moment Correction [1]

Upper Neck Load Cell	ATD	D(m)
1716, 2896, 3454, 3933, 2564, 4037	HIII - M95, HIII - M50, HIII - F05	0.01778
IF-2564, IF-205, IF-207, 555B/6UN	HIII - 10yo, HIII - 6yo, SID - IIs	0.01778
3454	THOR	0.0
2062	HIII - M50	0.00876
3303, IF-234	HIII - 3yo	0.0
2554, IF-954, 560G/6ULN	CRABI - 12mo, CRABI - 18mo	0.0058
2554, IF-954, 560G/6ULN	CRABI - 6mo, P1-1/2	0.0102
2331, 2587, IF-212, IF-235, 5583G/3ULN	P3/4, P3	0.0
4085, IF-240, 5552G/6UN	ES-2re	0.02
3715, IF-217, 5563G/6LN	Q series	0.0
4949, 4985	BioRID	0.01778
W50-71000, W50-71005	WorldSID	0.0195

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Lower Neck Moment Correction

$$\tag{Equation 1} M_x = M_{LC,\,x} - F_{LC,\,y}D_z$$ $$\tag{Equation 2} M_y = M_{LC,\,y} + F_{LC,\,x}D_z + F_{LC,\,z}D_x$$ $$\tag{Equation 3} M_z = M_{LC,z} - F_{LC,y}D_x$$ $$LC = Measured\,by\,lower\,neck\,load\,cell$$ $$M_x = Moment\,X\,at\,the\,base\,of\,the\,neck$$ $$M_y = Moment\,Y\,at\,the\,base\,of\,the\,neck$$ $$M_z = Moment\,Z\,at\,the\,base\,of\,the\,neck$$

Lower Neck Moment Correction [1]

Fixed Lower Neck Load Cell	ATD	$D_x$ (in)	$D_z$ (in)
1794, IF-242, IF-210	HIII - M95, HIII - M50	0.0508	0.0286
1794, IF-242, IF-210	BioSID	0.0508	0.0254
2150, 3251, 4541	HIII - F05	0.0445	0.0286
3166	SID - IIs	0.0445	0.0254
2430	HII - 6yo	0.0318	0.0237
5294	SID - H3	0.00	0.0127
4366	THOR 50th	0.00	0.0254
5575	THOR 5th	0.00	0.0191
W50-71000	WorldSID	0.00	0.0145
3300, 4365	EuroSID-1. ES-2re	0.00	0.022
3303. 3304	HIII - 3yo	0.00	0.0168
3715	Q - series	0.00	0.00
2554	CRABI - 6mo, CRABI - 12mo, CRABI - 18mo	0.00	0.0127

References

[1] SAE International. (2013). SAE J1733: Sign Convention for Vehicle Crash Testing. Society of Automotive Engineers.

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