Learning from Plants - A Biologically Inspired Multi-Cellular Approach towards Multi-Functional Adaptive Structure based on Fluidic Flexible Matrix Composite.

Abstract

Plants have many attractive characteristics for developing multi-functional adaptive structures, such as high strength and toughness per unit density, self-healing and reconfiguration, and nastic motion with short response time and large deformation. The vision of this thesis research is to develop enabling knowledgebase and design methodologies to synthesize plant-inspired adaptive structures. More specifically, investigations will focus on achieving multiple mechanical functionalities concurrently, such as actuation, variable mechanical properties, and vibration control. To reach this vision, this thesis research adopts the concept of multi-cellular structure based on the fluidic flexible matrix composite (F2MC) cells. Because such concept offers a natural platform to incorporate design inspirations from plants into artificial adaptive structure study, both at the local level of individual cell development and at the global level of structure architectural design and synthesis. This thesis research identifies several critical issues related to the development of F2MC based cellular adaptive structure. It investigates the dynamic characteristics of a multi-cellular structure, where F2MC cells with different configurations are connected to each other not only mechanically but also fluidically. It discovers new dynamic functionalities that are not feasible in an individual cell, including vibration isolation and dynamic actuation with enhanced authority within a designated frequency band. It provides a list of unique architectural designs of the cellular structure based on rigorous mathematical principles, and compares their performance to gain design insights. Finally, it derives novel and comprehensive synthesis procedures that are capable of selecting appropriate design variables for the F2MC cells, so that the cellular structure can achieve multiple performance targets concurrently, such as desired variable stiffness, actuation authority, and spectral data. The plant inspired design principles, physical knowledgebase and synthesis methodologies developed from this thesis fully manifests the rich functionalities and design versatilities of the F2MC based multi-cellular structure. They could foster the adoption of such novel adaptive structure concept to advance the state of art of many engineering applications, including aviation and aerospace, soft robotics, and intelligent civil infrastructure. The biologically inspired, multiple-cell oriented approach towards developing adaptive structure could also create a paradigm shift in other related academic research.