The effect of impact speed on the HIC obtained in pedestrian headform tests

Abstract

Pedestrian headform impact tests are generally carried out at a fixed impact speed, which varies depending on the test protocol in use. Thus, it may be desirable to extrapolate a single test result to higher and lower test speeds. This paper investigates the influence of impact speed on the Head Injury Criterion (HIC) and the peak dynamic displacement. The relationship between impact speed and these test measurements is first considered analytically using a linear spring model, and then empirically using the results of 29 headform tests on seven different locations. The results indicate that power functions can be used to predict the effect of impact speed, with exponents of approximately 2.5 for HIC and 0.8 for peak displacement. These relationships might be used for assessing head impact performance over a wider range of speeds than are presently tested.