Pelvis Resultant Acceleration

Overview

Pelvis resultant acceleration refers to the combined acceleration experienced by the pelvis in all three directions (X, Y, and Z) during a crash, representing the total force acting on this critical load-bearing region of the body [1]. If an Injury Assessment Reference Value (IARV) is associated with the Anthropomorphic Test Device (ATD) used in the selected load test, the calculated maximum pelvis resultant acceleration will additionally be reported as a percentage of the IARV [2]. 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 dummy's type, sex, and size [2].

Required Signals

• Acceleration at the Pelvis Center (X, Y, Z)

Calculation

1. Convert the pelvis acceleration to gravity (g) (if applicable)
2. Filter the pelvis acceleration (CFC = 600)
3. Calculate the resultant acceleration from the x, y, and z signals

$$Resultant\,Acceleration(t) = \tag{Equation 1}\sqrt((a_{x}(t))^2 + (a_{y}(t))^2 + (a_{z}(t))^2)$$

4. Calculates the maximum resultant acceleration value
5. Calculates the percent of the IARV threshold that the calculated maximum resultant acceleration reaches

Pelvis Resultant Acceleration IARV Table [3]

ATD	IARV (G's)
WorldSID	77

References

[1] Forman J, Lessley D, Kent R, Bostrom O, Pipkorn B. Whole-body kinematic and dynamic response of restrained PMHS in frontal sled tests. Stapp Car Crash J. 2006 Nov;50:299-336.

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

[3] Louden A. "Dynamic Side Impact Testing with the 50th Percentile Male WorldSID Compared to the ES-2RE". National Highway Traffic Safety Administration, Paper Number: 09-0296.