Impact Damage Tolerance of Hierarchical Structures in Biological Composites

Abstract

The aim of this research is to examine the factors of bio-composite microstructures that affect their damage tolerance. Many animals with natural armor succeed in protecting themselves by retaining structural integrity after impact. These natural armor shells, exoskeletons, and scales have hierarchical structures that outperform homogeneous materials in damage tolerance, energy absorption, and fracture resistance. A ply of aligned fibers made of either elastic or rigid materials forms the basis of their structure. Various sizes and quantities of layers are staggered at different angles to resemble unidirectional, quasi-isotropic, helicoidal, and other layups. These structural factors in the microstructure of certain animals function together to provide extra toughness before failure. The toughening mechanisms and material properties in the natural armor of mantis shrimp, Japanese beetle, and arapaima fish will be studied. A dominant structural characteristic can be identified to increase damage tolerance by comparing the performance of manufactured composites influenced by these species. Data obtained from literature review, such as residual strength, will be used to measure the structural factors of a composite to increase damage tolerance. This research will aid in armor material design and maximize the potential for impact-resistant bioinspired designs.