Pubic Symphysis Force

Overview

Lateral force measured at the pubic symphysis refers to the forces acting on either side of the pubic symphysis during a car crash [1]. High levels of laterally applied force to the pubic symphysis can result in pelvic fractures, internal bleeding, or lumbar spine damage [2]. Additionally, if an Injury Assessment Reference Value (IARV) is associated with the ATD used in the selected load test, the calculated maximum lateral force will be reported as a percentage of the IARV [3]. The IARV represents a threshold value used to assess the risk of injury during an impact. Each ATD has its own IARV, which varies depending on the type, sex, and size of the dummy [3].

Pubic Symphysis Location

Required Signals

• Force at the Pubic Symphysis (Y)

Calculation

1. Convert the pubic symphysis force to newtons (N) (if applicable)
2. Filter the pubic symphysis force (CFC = 600)
3. Signal is truncated to start at 0 seconds (if applicable)
4. Finds the maximum absolute filtered force
5. Calculates the percent of the IARV threshold that the calculated maximum absolute pubic symphysis force reaches

Pubic Symphysis Force IARV Table [4]

ATD	IARV (N)
EuroSID	6000

NCAP Combined Injury Rating

The pelvis force metric for ES-2re is used for the NCAP side MDB and side pole tests.

$$\tag{Equation 1}P_{pelvis}(3+) = \frac{1}{1+e^{(7.5969-0.0011*F)}}$$

NCAP Probability of Injury for Pelvis Force for ES-2re [5]

References

[1] Leport, T., Baudrit, P., Trosseille, X., Petit, P., Palisson, A., & Vallancien, G. (2007). Assessment of the pubic force as a pelvic injury criterion in side impact. SAE Technical Paper 2007-22-0019.

[2] Tile, M., Helfet, D., & Kellam, J. (2003). Fractures of the Pelvis and Acetabulum.

[3] "Frontal Offset Crashworthiness Evaluation". Guidelines for Rating Injury Measures, Insurance Institute for Highway Safety, June 2009.

[4] Federal Motor Vehicle Safety Standard 49 CFR § 571.214; Side impact protection.

[5] National Highway Traffic Safety Administration. Final Rule; Response to Petitions for Reconsideration: Federal Motor Vehicle Safety Standards; Head Restraints. Docket No. NHTSA-2006-26555-0120, U.S. Department of Transportation, 2006.