27 - 06 - 2016 15 - Nov - 2012 14 - Nov - 2015

Number of Papers published in peer-reviewed journals: Final Report: High Resolution Electron Microbeam Examination and 3D reconstruction of Alligator Gar Scale Report Title Engineered laminate composites have been widely used by public and private sectors due to their high strength-to-weight and high stiffnessto-density ratios. However, engineered composites tend to be brittle, and are consequently vulnerable to delamination when impacted or penetrated when compared to biocomposites. We have completed a careful characterization of the internal structure of one such biolaminate–the scales of the alligator gar fish (Atractosteus spatula). The scales of the alligator gar are similar to teeth and possess remarkable delamination resistance when hydrated. In order to understand this resistance, it was critically important to properly characterize the various components of the scale and their interfaces. In the course of this study, we have determined: (1) the hierarchical structure of the gar scale from the millimeter down to the nanometer length scale, (2) the first detailed description of chemical variations within the gar scale, (3) the nature of the interface between the hard outside portion of the scale and the boney interior, and (4) provided the detailed structural and chemical information to ERDC for use in the development of the In-House Meso-Scale Scientific and Engineering-Discrete Element Problem Solver (SE-DEPS) model. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published that acknowledge ARO support from the start of the project to the date of this printing. List the papers, including journal references, in the following categories: (b) Papers published in non-peer-reviewed journals (N/A for none) Received Paper