154. STRUCTURE AND TOUGHENING MECHANISM OF COELACANTH SCALES
Name: Haocheng Quan
Grad Year: 2018
Coelacanth (Latimeria chalumnae) plays an important role in evolution because it bridges the evolutionary gap between fish and tetrapods. After 300 million years, this living fossil still retains many of its original characteristics. The body is armored by the highly modified cosmoid scales, which can only be found on extinct fish. The fish scales are overlapped on the fish body; the exposed region is highly mineralized and very rough, which helps protect the fish from predators. The scale has a highly mineralized outer layer and collagenous inner layers, which is called isopedine.. The collagen fibers form a layer which are orientated almost perpendicular to the fibers in the adjacent layer, but successive bilayers show a progressive right-handed twisting arrangement. The unique architecture results in an in-plane isotropic mechanical behavior. More loosely packed interbundle fibrils are founded and they run through the whole thickness of the scale, acting like ropes to tie up the fiber bundles. Such interplanar connection is considered as a feasible toughening mechanisms compared to other fish scales without such structure.
Industry Application Area(s)
Aerospace, Defense, Security | Civil/Structural Engineering | Materials