Compression-based injury variables from chestbands in far-side impact THOR sled tests.

This study seeks to determine compression () and compression-related injury variables (velocity and viscous injury criterion: and ) from chestband data in pure lateral and oblique far-side impact sled tests. The 3-point belt-restrained mid-sized male Test Device for Human Occupant Restraint (THOR) dummy was placed on a buck and subjected to side impacts with and without center-mounted airbags. The change in velocity was 8.3 m/s for all conditions. Two chestbands were routed around the outer circumference of the THOR at the levels of the third and sixth ribs. Maximum chest deflections were computed using strain gauge signals from the chestbands and their temporal contours. Three methods were used to determine deflection metrics. The first method paralleled methods used in previously published human cadaver studies; the second method used the actual anchor point location and actual alignment of the dummy's internal sensors; and the third method used the anchor location of the internal sensor but determined the sensor's locations on the contour confining to the aspect of the sensor. These 3 approaches are abbreviated as the SD, ID, and TD variables. The injury variables , , and were determined according to accepted procedures. Their peak magnitudes were extracted and an evaluation of their accuracy was made based on the SD method. The average SD-based magnitudes for the upper and lower chest levels were 0.12 and 0.17 m/s, the magnitudes were 5.3 and 1.8 m/s, and the magnitudes were 0.24 and 0.15 m/s, respectively. Other data are given for all variables at the 2 levels of the thorax in the body of this paper. The ID-based peak variables were the lowest, and this observation was true regardless of the aspect, right or left side. In contrast, the SD method produced the greatest magnitudes of the variables. The variable had the greatest normalized difference among all 3 injury variables. Though the present study is limited in scope, the predetermined placement of the internal sensors in the THOR dummy underpredicted chest deflection-related injury variables, and the viscous criterion was the least reliable variable in these lateral and oblique far-side impact sled tests.