synthesis of shape morphing compliant mechanisms btrease/share/kjlu- of shape morphing compliant...

Download Synthesis of Shape Morphing Compliant Mechanisms btrease/share/KJLU-  of Shape Morphing Compliant Mechanisms by ... Professor Sridhar Kota, Chair ... Topology information for the shape morphing compliant mechanisms in

Post on 12-Apr-2018

212 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • Synthesis of Shape Morphing Compliant Mechanisms

    by

    Kerr-Jia Lu

    A dissertation submitted in partial fulfillment of the requirements of the degree of

    Doctor of Philosophy (Mechanical Engineering)

    in The University of Michigan 2004

    Doctoral Committee: Professor Sridhar Kota, Chair Professor Debasish Dutta Professor Peretz P. Friedmann

    Associate Professor Kazuhiro Saitou

  • ii

    For Mom, Dad, my sister, Kerr-Hsin,

    and

    My loving husband, Jia-Hsuan.

    Thank you for all your love and support.

    Thank you for being my best friends and always being there for me.

  • iii

    ACKNOWLEDGEMENTS

    I would like to thank my advisor, Professor Sridhar Kota, for his guidance and

    support in the development of this research. His vision and insight in design have

    constantly motivated me throughout my graduate study. I am grateful for the opportunity

    he gave me to develop my ideas freely and to think independently. I would not have

    come thus far without his guidance and encouragement. He has been a great mentor who

    helped me grow as a researcher and as a person. He has made my graduate study a

    wonderful experience. I also want to thank Professor Sridhar Kota for encouraging me to

    pursue an academic career and giving me valuable advices during my job search.

    I would like to thank Professor Kazuhiro Saitou for his advices on my research,

    which started out as a term project in his Discrete Optimization course. The genetic

    algorithm covered in the course has inspired the initial development of my research and

    has become essential to this work as it proceeds. His comments during our meetings have

    also deepened my understanding of my research.

    I also want to thank my other committee members, Professor Peretz Friedmann

    and Professor Debasish Dutta, for their valuable suggestions and insightful questions

    regarding this work, especially in the problem formulation and the morphing aircraft

    examples.

    I have also learned a lot from previous and current colleagues working in the

    Compliant Systems Design Laboratory (CSDL). Discussions with Dr. Mary Frecker, Dr.

  • iv

    Joel Hetrick and Dr. Jinyong Joo have enhanced my understanding of the fundamental

    design issues in compliant mechanisms. I am also very grateful for their advices for my

    future career plan. I want to thank Mr. Charles Kim, Mr. Brian Trease, Mr. Tanakorn

    (Tony) Tantanawat, Ms. Christine Vehar, Mr. Michael Cherry, and Mr. Zackary Kreiner,

    whom I see day in and day out in CSDL, for always letting me bounce ideas off of them.

    The countless discussions in the lab have always been very inspiring. All the other non-

    academic activities in the lab have also made my graduate study unforgettable.

    I want to thank Mr. Kuei-Yuan (Miles) Chan, for his suggestions on local search

    algorithms. Thanks to Mr. Cheng-Yu (Shower) Lin for motivating the structural design

    examples and to Mr. Shih-Fen Cheng for offering advice on various optimization

    algorithms.

    Finally, I would like to acknowledge the funding support of the U.S. Air Force

    Office of Scientific Research (contract #F49620-96-1-0205) and the Navel Research

    Laboratory (contract #N66001-02-C-8061).

  • v

    TABLE OF CONTENTS

    DEDICATION................................................................................................................... ii ACKNOWLEDGEMENTS ............................................................................................ iii LIST OF TABLES ........................................................................................................... ix LIST OF FIGURES ......................................................................................................... xi CHAPTER 1: INTRODUCTION TO COMPLIANT MECHANISMS ...................... 1

    1.1 Compliant Mechanisms ...................................................................................... 1 1.1.1 Classification of Compliant Mechanisms ....................................................... 2 1.1.2 Advantages of Compliant Mechanisms .......................................................... 4 1.1.3 Areas of Applications ..................................................................................... 5

    Design-for-No-Assembly............................................................................................ 5 Actuator Tailoring....................................................................................................... 6 Material Property Synthesis........................................................................................ 7 Micro- and Nano-electromechanical Systems (MEMS and NEMS).......................... 8 Precision Engineering ................................................................................................. 9 Bi-Stable Mechanisms .............................................................................................. 10 Adaptive Structures................................................................................................... 11

    1.2 Shape Morphing Systems ................................................................................. 11 1.2.1 Conventional Rigid-Link Mechanisms ......................................................... 12 1.2.2 Smart Material Actuators.............................................................................. 13 1.2.3 Compliant Mechanisms ................................................................................ 16 1.3 Compliant Mechanism Literature Review........................................................ 18 1.3.1 Kinematics Approach.................................................................................... 18

    Flexural Pivots and Flexible Members ..................................................................... 19 Pseudo-Rigid-Body Model ....................................................................................... 19 Shape Morphing Designs.......................................................................................... 21

    1.3.2 Structural Optimization Approaches............................................................. 21 Continuous Optimization: Mathematical Programming........................................... 22 Discrete Optimization: Heuristic, Evolutionary, and Others .................................... 26 Shape Morphing Designs.......................................................................................... 30

    1.4 Scope of Investigation....................................................................................... 30 1.5 Organization of The Dissertation...................................................................... 32

    CHAPTER 2: SYNTHESIS OF COMPLIANT MECHANISMS.............................. 33 2.1 Topology, Size, and Geometry of Compliant Mechanisms.............................. 33 2.2 Design Domain Parameterization ..................................................................... 36 2.2.1 Continuum-Based Approach......................................................................... 36 2.2.2 Ground Structure Approach.......................................................................... 41 2.3 Optimization Problem....................................................................................... 44

  • vi

    2.3.1 Objective Functions ...................................................................................... 44 2.3.2 Optimization Methods .................................................................................. 47

    Continuous Optimization .......................................................................................... 47 Discrete Optimization ............................................................................................... 49

    2.4 Research Issues for Shape Morphing Compliant Mechanisms......................... 50 CHAPTER 3: PROBLEM STATEMENT ................................................................... 53

    3.1 Design Objective............................................................................................... 53 3.2 Design Specifications and Assumptions........................................................... 54 3.3 Synthesis Approach Overview.......................................................................... 56

    CHAPTER 4: DESIGN DOMAIN INITIALIZATION .............................................. 58 4.1 Task Feasibility Analysis.................................................................................. 58 4.1.1 Feasibility Check Example ........................................................................... 60 4.2 Output Point Identification ............................................................................... 62 4.2.1 Output Point Identification Example ............................................................ 65

    CHAPTER 5: DESIGN DOMAIN PARAMETERIZATION .................................... 67 5.1 Defining the Design Domain ............................................................................ 67 5.2 Binary Ground Structure Parameterization....................................................... 68 5.2.1 Design Variables........................................................................................... 70

    Parameters................................................................................................................. 71 Number of Design Variables .................................................................................... 71 Finite Element Mesh Mapping...............................................................