Influence of System Variables on Interior Head Impact Testing

Head Impact Criterion (HIC) numbers obtained from interior head impact testing with the NHTSA-designed Free Motion Headform (FMH) are influenced by many variables. The high level of variability experienced in the NHTSA-proposed Interior Head Impact Test presents a challenge to today's automotive engineers. Primary contributors to HIC variability include (1) impact speed, (2) headform calibration performance, (3) design/build part variation, and (4) target point impact accuracy. This study shows that controlling these variables during testing can improve test data repeatability and reproducibility, as well as reduce design and testing time.