KOSEN 한인과학기술자네트워크

Introduction
-Background
-Wing loading in flight
-Bending and torsion
Thin, dense exterior with reinforcing internal structures
-Thin, dense exterior
-Reinforcing internal structures
-Ridges
-Struts and foam
Efficiently tailored designs based on specific conditions
-The effect of bird body mass on the wing bone and feather
--Wing bone
--Flight feather
-The effect of flight style and diving on the wing bones and feathers
--Wing bones
--Flight feathers
Hierarchical composite
-Avian bone: from nanostructure to mesostructure
-The feather: from nanostructure to mesostructure
Bioinspired and analogous synthetic designs
-Dense exterior for lightweight torsion resistance
-Reinforced internal structures for increased stiffness
-Hierarchical composite design
-Avian wing design
-Future outlook on avian feather- and bone-inspired designs
Conclusions

자동차는 물론 우주항공에 이르기까지 운송수단에 있어서 경량화 소재에 대한 중요성은 날로 높아지고 있다. 고차원의 다층구조로 존재하는 새의 깃털과 뼈는 자연계에 존재하는 고내구성 고강도의 경량 소재이다. 새로운 소재를 가장 쉽게 착안할 수 있는 방법은 자연계를 모방하여 실험적 확인을 통해 산업적으로 구현하는 것이다. 새의 깃털과 뼈는 우리가 원하는 경량화 소재의 실현 방안을 제시해 줄 수 있을 것이다. 본 문헌을 통해 경량화 소재에 대한 관심을 높이는 계기가 될 수 있을 것이다.
Abstract
Flight is not the exclusive domain of birds; mammals (bats), insects, and some fish have independently developed this ability by the process of convergent evolution. Birds, however, greatly outperform other flying animals in efficiency and duration; for example the common swift (Apus apus) has recently been reported to regularly fly for periods of 10 months during migration. Birds owe this extraordinary capability to feathers and bones, which are extreme lightweight biological materials. They achieve this crucial function through their efficient design spanning multiple length scales. Both feathers and bones have unusual combinations of structural features organized hierarchically from nano- to macroscale and enable a balance between lightweight and bending/torsional stiffness and strength. The complementary features between the avian bone and feather are reviewed here, for the first time, and provide insights into nature's approach at creating structures optimized for flight. We reveal a novel aspect of the feather vane, showing that its barbule spacing is consistently within the range 8？16 μm for birds of hugely different masses such as Anna's Hummingbird (Calypte anna) (4 g) and the Andean Condor (Vultur gryphus) (11,000 g). Features of the feather and bone are examined using the structure-property relationships that define Materials Science. We elucidate the role of aerodynamic loading on observed reinforced macrostructural features and efficiently tailored shapes adapted for specialized applications, as well as composite material utilization. These unique features will inspire synthetic structures with maximized performance/weight for potential use in future transportation systems.