Comparative analysis of manual and 3D scanning methods for backface deformation on anatomically complex surfaces

This study compared a traditional and a novel method for measuring backface deformation in body armor testing. The traditional method, defined in ASTM E3068–20, employs a bridge with a depth gauge that contacts the backface witness material during measurement, whereas the novel approach uses an Artec Eva handheld structured-light 3D scanner and Geomagic Control X software to obtain digital, non-contact measurements. Ballistic tests were conducted on an anatomically realistic female Roma Plastilina No. 1 clay manikin wearing soft unisex body armor. Using 9 mm Luger FMJ RN rounds, impacts were delivered to three anatomical locations: the xiphoid process, inframammary region, and superior medial chest. Results showed no statistically significant overall difference between measurement methods, but agreement between methods varied by anatomical location. Manual measurements tended to yield deeper deformation depths at the inframammary region where deformations were less uniform, suggesting that complex surface geometry influences measurement differences between methods.