UC San Diego UC San Diego Electronic Theses and Dissertations Title Avian Feathers: An Examination of Lightweight Resilience and Bioinspired Designs Permalink https://escholarship.org/uc/item/9s34g3f8 Author Sullivan, Tarah Publication Date 2017 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA, SAN DIEGO Avian Feathers: An Examination of Lightweight Resilience and Bioinspired Designs A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Materials Science and Engineering by Tarah Naoe Sullivan Committee in charge: Professor Marc A. Meyers, Chair Professor Shengqiang Cai Professor Vlado A. Lubarda Professor Joanna McKittrick Professor Jan B. Talbot Professor Michael T. Tolley 2017 Copyright Tarah Naoe Sullivan, 2017 All rights reserved. The Dissertation of Tarah Naoe Sullivan is approved, and it is acceptable in quality and form for publication on microfilm and electronically: Chair University of California, San Diego 2017 iii DEDICATION This work is dedicated to my family. iv EPIGRAPH In all things of nature there is something of the marvelous. Aristotle v TABLE OF CONTENTS SIGNATURE PAGE ......................................................................................................... iii DEDICATION .................................................................................................................. iv EPIGRAPH ....................................................................................................................... .v TABLE OF CONTENTS .................................................................................................. vi LIST OF FIGURES .......................................................................................................... .x LIST OF TABLES……………………………………………………………………...xvii ACKNOWLEDGEMENTS …………………………………………………………...xviii VITA ……………………………………………………………………………………xxi ABSTRACT OF THE DISSERTATION ……………………………………………..xxiii 1. Introduction and Objectives .................................................................................... 1 1.1. Bioinspiration and Materials Science ................................................................. 1 1.2. Research Focus and Motivation .......................................................................... 2 1.3. Research Objectives ............................................................................................ 5 2. Background ............................................................................................................. 6 2.1. Evolution of Birds and Feathers ......................................................................... 6 2.2. Bird Wing Background ....................................................................................... 8 2.3. Wing Loading in Flight ..................................................................................... 11 2.3.1. Bending and Torsion ............................................................................. 12 2.4. Wing Design Concepts: Wing Bones and Feathers .......................................... 14 2.4.1. Thin, Dense Exterior ............................................................................. 15 2.4.2. Reinforcing Internal Structures ............................................................. 21 2.5. Efficiently Tailored Designs Based on Specific Conditions............................. 23 2.5.1. The Effect of Flight Style and Diving on Wing Bones ......................... 25 2.5.2. The Effect of Flight Style and Diving on Flight Feathers .................... 27 2.6. Differences Between Wings of Birds and Pterosaurs and Bats ........................ 28 2.7. Feather Background .......................................................................................... 30 2.7.1. The Importance of Feathers for Flight .................................................. 30 2.7.2. Feather Types and Structure ................................................................. 31 2.7.3. Feather Composition ............................................................................. 34 2.7.4. Mechanical Properties of the Flight Feather ......................................... 36 2.8. Natural Adhesives ............................................................................................. 37 2.9. Shape Memory Polymers .................................................................................. 40 2.10. Conclusions ................................................................................................... 42 2.11. Acknowledgements ....................................................................................... 43 vi 3. Scaling Relationships of Bird Wings and Feathers for Efficient Flight ............... 44 3.1. Introduction ....................................................................................................... 44 3.2. Materials and Methods ...................................................................................... 49 3.2.1. Avian Bone Specimens ......................................................................... 49 3.2.2. Avian Bone Characterization ................................................................ 49 3.2.3. Feather Specimens ................................................................................ 50 3.2.4. Feather Characterization ....................................................................... 50 3.2.5. Data from Literature ............................................................................. 50 3.3. Results and Discussion ..................................................................................... 51 3.3.1. Allometric Scaling of Avian Wing Bone Due to Materials Limit ........ 51 3.3.2. Allometric Scaling of Wing Bone to Accommodate Flight Style ........ 53 3.3.3. Scaling Trends Observed in the Avian Feather .................................... 59 3.4. Conclusions ....................................................................................................... 64 3.5. Acknowledgements ........................................................................................... 65 4. Resilience of Feather Barbs .................................................................................. 67 4.1. Introduction ....................................................................................................... 67 4.2. Materials and Methods ...................................................................................... 71 4.2.1. Test Specimens ..................................................................................... 71 4.2.2. Mechanical Tests .................................................................................. 71 4.2.3. Scanning Electron Microscopy ............................................................. 72 4.2.4. Computer Aided-Design Measurements ............................................... 73 4.2.5. Finite Element Modeling ...................................................................... 73 4.2.6. Statistical Analysis ................................................................................ 74 4.3. Theory and Calculations ................................................................................... 74 4.3.1. Elastic Modulus of the Barb’s Foam-filled Center ............................... 74 4.3.2. Simplified Block Model of Single Barb Deflection ............................. 75 4.3.3. Analytical Model of Single Barb Deflection ........................................ 79 4.3.4. Finite Element Model of a Single Barb in Flexure ............................... 80 4.4. Results and Discussion ..................................................................................... 80 4.4.1. Materials Characterization .................................................................... 80 4.4.2. Cyclic Testing of Single Barbs ............................................................. 83 4.4.3. Linear Deflection of Single Barbs ........................................................ 86 4.4.4. Comparison between the Experimental Results and Models ................ 87 4.4.5. Deflection of Multiple Barbs ................................................................ 90 4.4.6. Strengthening Mechanisms of the Feather Vane .................................. 91 4.5. Conclusions ....................................................................................................... 92 4.6. Acknowledgements ........................................................................................... 92 5. Feather Barbules ................................................................................................... 94 5.1. Introduction ....................................................................................................... 94 5.2. Materials and Methods ...................................................................................... 99 5.2.1. Feather Samples .................................................................................... 99 5.2.2. Feather Vane Adhesion ......................................................................... 99 5.2.3. Barbule Flexure Tests ......................................................................... 100 5.2.4. Wind Tunnel Test Specimens and Setup ............................................ 102 5.2.5. Wind Tunnel: Barbule Adhesion and Air Capture ............................. 103 vii 5.2.6. Wind Tunnel: Directional Permeability of the Vane .........................