Meeting Abstract
The sharpness of biological puncturing tools plays an integral role in their function, as initiating fracture in a target material depends on the shape of the tool tip. There are various approaches to measuring tool sharpness, but how the different aspects of morphology affect puncture has yet to be studied. To understand what features of puncture tool tip affect the puncturing force, we turn to vipers as a case study. Viper strike is a quick, venomous bite and release that incapacitates prey and reduces their likelihood of injury. To understand the relationship between fang tip shape and fracture initiation, we took a two-pronged approach: 1) by measuring total fang length, tip sharpness index, tip surface area, and average included angle of fangs from 19 species and comparing these to the amount of force required to initiate fracture; and 2) creating and testing engineered puncture tools to separate the functional impact of included angle and radius of curvature on puncture initiation. When comparing the effect of fang tip morphology, only included angle showed a significant impact of force to initiate fracture, relative to the other morphological measurements. For the engineered punches, both included angle and radius of curvature have a significant effect on the force required to initiate fracture, with included angle having a greater impact. These data suggest that fang included angle is the strongest predictor of the force required to initiate fracture. Radius of curvature, which is used to determine sharpness index, is also an important predictor, though the influence of this factor becomes less significant at larger included angles.
