The Effects of Body-Borne Equipment Weight on ATD Lumbar Loads Measured During Crashworthy Seat Vertical Dynamic Tests

Advanced computer simulation was utilized to investigate the effects of adding high mass to the upper torso of an anthropomorphic test device (ATD) while it occupied a crashworthy seat during a typical vertical dynamic crash pulse. The modeling cases included three different ATD sizes, three seat stroking weights, and four methods of selecting the seat’s vertical-load-limiting (energy-absorber) threshold. The peak ATD lumbar load and the maximum seat stroke were calculated for standard-weight ATDs and also for those with high mass added to the upper torso. The results of 63 modeling cases were tabulated and are presented in graphical form so that trends can be readily identified. The worst-case modeled result showed that the peak lumbar load of the 5th-percentile ATD can increase by over 60 pct with 37.1 lb added to the upper torso. While the modeling parameters were intentionally selected to show ATD lumbar load amplification, they did not represent the actual maximum allowed equipment weight, which can be well over 60 lb. It is suggested that additional analysis and research be conducted to investigate the potential human injury effects of adding high equipment weight to the upper torso.