Biomimetics: Advancing Man-Made Materials Through Guidance From Nature

Abstract

“The X–29 and HI–MAT use on–board computers to provide greater flexibility. Designers hope that someday these techniques will give man–made flying machines the agility of a dragonfly, which can hover and change direction almost instantly in its search for food.” (Footnote on a display at the National Air & Space Museum, Washington, D.C., August 1990) Future technological advances are becoming increasingly dependent on our ability to design and produce materials with specific thermomechanical and electronic properties. The projected structural and electronic performance requirements for materials are unprecedented. The realization of corresponding technological goals will require significant scientific and technical breakthroughs fueled by innovative thinking. Biomimetics attempts to tap a virtually inexhaustible source of ideas and inspiration: naturally–evolved systems. Mankind has long marveled at the efficiency and effectiveness of biologically–evolved structural systems. Biologists have studied exhaustively the time–proven processes that natural systems employ for synthesizing multifunctional materials with unparalleled precision, thus enabling the species to survive and prosper. The prospect of mimicking biological synthesis in producing man–made materials has generally appeared to be an impossible task. In recent years, however, revolutionary advances in our ability to probe the fabric of materials down to their atomic structures and in the processing control of advanced materials’ microstructures have fueled a renewed interest in imitating natural processes, initially in the laboratory, and ultimately, at the industrial scale. Engineering and scientific communities have a fundamental role to play in this new revolutionary and promising endeavor. The benefits to specific thermomechanical properties resulting from each microstructural feature designed into the biological system have to be understood and quantitatively catalogued. Recommendations for incorporating architectural features encountered in nature in customized man–made systems must be based on engineering analysis of the property enhancement resulting from each observed physical mechanism. This paper addresses a few specific examples of nature’s ingenuity in building–in features which advance properties such as strength, impact resistance, damage control through multiple fracture–energy absorbing paths, and built–in damage–assessment and repair–activating sensors. Potential benefits to advanced artificial materials through inspiration derived from understanding the function of natural materials are also discussed.