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Smart Materials and New Technologies For the architecture and design professions D.. Preface vii1 Materials in architecture and design 1 1.1 Materials and architecture 2 1.2 The contempo

SMART MATERIALS AND NEW TECHNOLOGIES

Smart Materials and New Technologies For the architecture and

design professions

D Michelle Addington

Daniel L Schodek

Harvard University

Architectural Press

An imprint of Elsevier

Linacre House, Jordan Hill, Oxford OX2 8DP

30 Corporate Drive, Burlington, MA 01803

First published 2005

Copyright # 2005 All rights reserved

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Preface vii

1 Materials in architecture and design 1 1.1 Materials and architecture 2 1.2 The contemporary design context 5 1.3 The phenomenological boundary 7 1.4 Characteristics of smart materials and systems 8 1.5 Moving forward 11 1.6 Organization of the text 13

2 Fundamental characterizations of materials 21 2.1 Traditional material classification systems 22 2.2 Alternative classification systems 27 2.3 Classification systems for advanced and smart

2.4 The internal structure of materials 31 2.5 Properties of materials 38 2.6 General classes of materials 41 2.7 Nanomaterials 44

3 Energy: behavior, phenomena and environments 46 3.1 Fundamentals of energy 46 3.2 Laws of thermodynamics 47 3.3 The thermodynamic boundary 51 3.4 Reconceptualizing the human environment 54 3.5 The thermal environment 55 3.6 The luminous environment 64 3.7 The acoustic environment 72

4 Types and characteristics of smart materials 79 4.1 Fundamental characteristics 79 4.2 Type 1 smart materials – property-changing 83 4.3 Type 2 smart materials – energy-exchanging 95

5 Elements and control systems 109 5.1 Sensors, detectors, transducers and actuators: definitions and characterization 114 5.2 Control systems 127 5.3 MEMS (micro-electrical mechanical systems) 131 5.4 Sensor networks 134 5.5 Input/output models 135

6 Smart products 138 6.1 A phenomenological perspective 138

Contents v Contents

Smart Materials and New Technologies

vi Contents

6.2 Product technologies and forms 142 6.3 Smart material product forms 144

7 Smart components, assemblies and systems 163 7.1 Fac¸ade systems 165 7.2 Lighting systems 173 7.3 Energy systems 180 7.4 Structural systems 185

8 Intelligent environments 198 8.1 The home of the future 199 8.2 From the architect’s view to the technologist’s

8.3 Characterizations of intelligent environments 203 8.4 Complex environments 216

9 Revisiting the design context 218

Ten years ago, when we first began treading in the murky waters of ‘‘smart’’ materials and micro-systems, we had little information to guide us Although there had already been rapid expansion in these technologies in the science and engineering fields, particularly in regard to sensor develop-ment, their entry into the design arena was, at best, idiosyncratic We found many novelty items and toys – mugs that changed color when hot coffee was poured inside, and rubber dinosaurs whose heads bobbed when connected

to a battery – and we noted that many designers were beginning to incorporate the language of smart materials, albeit not the technologies themselves There were proposals for buildings to be entirely sheathed with ‘‘smart’’ gel, or for

‘‘smart’’ rooms that would deform individually for each occupant according to their specific physiological and psy-chological needs Precisely how this would happen remained mysterious, and it was often presumed that the magical abilities attributed to the smart designs were simply techni-calities that someone else – an engineer perhaps – would figure out

These proposals troubled us from two aspects The first was clearly that designers were considering these very new and sophisticated materials and technologies to fit right into their normative practice, making design simpler as the manifesta-tion of intenmanifesta-tions could shift from the responsibility of the designer to the material itself One would no longer have to carefully and tediously design wall articulation to create a particular visual effect, as the material would be capable of creating any effect, one only had to name it In addition to this abdication of responsibility to an as-yet undefined tech-nology, we were also concerned with the lack of interest in the actual behavior of the technology By framing these technologies from within the design practice, architects and designers were missing the opportunity to exploit unprece-dented properties and behaviors that should have been leading to radically different approaches for design rather than only to the manifestation of designs constrained by the hegemony of existing practice

When we looked at the other end of the spectrum to examine what scientists and engineers were doing, however,

we encountered equally problematic responses Much of the

Preface vii Preface

early development had been geared toward miniaturization and/or simplification of existing technologies – using instan-taneous labs on a chip to reduce the time of the unwieldy chromatography process; replacing complex mechanical valves with seamless shape memory actuators As manufactur-ing processes were adapted to these specialized materials, and advances in imaging allowed fabrication at the nano scale level, the development shifted from problem solving to

‘‘technology push.’’ Countless new materials and technolo-gies emerged, many looking for a home, and a potential application

We were confronted with trying to fit round pegs – highly specific technologies – into square holes – incredibly vague architectural aspirations Neither end seemed appropriate We did not have the kind of problems that a new technology could easily step in to solve, nor did we have any idea about just what kind of potential could be wrung from the behaviors

of these technologies We needed to bridge the very large gap between the owners of the relevant knowledge and the inventors of the potential applications

This transfer of knowledge has not been easy Scientific and engineering information typically enters the design realm already ‘‘dumbed down.’’ Architects and designers don’t need to know how something works, they just need to know the pragmatics – how big is it, what does it look like? This approach, unfortunately, keeps the design professions at arm’s length, preventing not only the full exploitation of these technologies, but also denying a coherent vision of the future to help direct development in the science and engineering disciplines Over the last ten years, we have struggled in our own research, and in our classes, to find the fluid medium between knowledge and application, so that both are served This book represents the culmination of that decade of investigation and experimentation

Our primary intention for the book’s content was the development of a coherent structure and language to facilitate knowledge transfer at its highest level There are certain phenomena and physical properties that must be fully understood in order to design a behavior Fundamental for architects and designers is the understanding that we cannot frame these technologies within our own practice, we must instead inflect their deployment based on their inherent characteristics For example, as evidenced by the continuing desire of architects to produce smart facades, we have a tendency to ask these technologies to act at our normative scale – the scale of a building Most of these technologies, however, perform at the molecular and micro-scales How

Smart Materials and New Technologies

viii Preface

differently might we think and design if we engaged these scale differences rather than ignoring them?

Clearly, the knowledge about these materials and technol-ogies within the science and engineering realms is so vast that any given engineer will have a different knowledge set than another, even in the same area of specialty What knowledge, then, should we bring across the divide to the designers? We identified some fundamental laws of physics and principles of materials science that we felt could serve as the building blocks to allow the derivation of behaviors most relevant to the design professions Several different materials, compo-nents and assemblies were then chosen and described to illustrate how these building blocks could be applied to help understand and ultimately exploit each example’s character-istics We fully expect that the specific materials and technologies referred to in this book will soon become obsolete, but we strongly believe that the theoretical structure developed herein will transcend the specifics and be applic-able to each new material that we may confront in the future

Michelle Addington Cambridge, Massachusetts

Preface ix Smart Materials

We are grateful to the many students over the last decade who have willingly experimented with unfamiliar materials and technologies in our courses as we explored the untapped possibilities inherent in thinking about architecture as a network of transient environments A number of these students have directly supported the development of this book; in particular, our teaching assistants and fellows: John

An, Nico Kienzl, Adriana Lira, Linda Kleinschmidt, and Andrew Simpson Nico, as our first doctoral student in the area, was instrumental in helping us transition to more direct hands-on workshops for the students, and John, our most recent doctoral student in the area, spearheaded a spin-off course that uses simulation techniques We would also like to thank the two chair-persons of the architecture department – Toshiko Mori and Jorge Silvetti – who supported the devel-opment of coursework in this area that helped lead to this book And always, we are fortunate to have excellent faculty colleagues that we invariably rely upon for support, including Marco Steinberg, Martin Bechthold, and Kimo Griggs

Michelle Addington and Daniel Schodek

Acknowledgments

Acknowledgments xi

Smart planes – intelligent houses – shape memory textiles – micromachines – self-assembling structures – color-changing paint – nanosystems The vocabulary of the material world has changed dramatically since 1992, when the first ‘smart material’ emerged commercially in, of all things, snow skis Defined as ‘highly engineered materials that respond intelli-gently to their environment’, smart materials have become the ‘go-to’ answer for the 21st century’s technological needs NASA is counting on smart materials to spearhead the first major change in aeronautic technology since the develop-ment of hypersonic flight, and the US Defense Departdevelop-ment envisions smart materials as the linchpin technology behind the ‘soldier of the future’, who will be equipped with everything from smart tourniquets to chameleon-like cloth-ing At the other end of the application spectrum, toys as basic as ‘Play-Doh’ and equipment as ubiquitous as laser printers and automobile airbag controls have already incor-porated numerous examples of this technology during the past decade It is the stuff of our future even as it has already percolated into many aspects of our daily lives

In the sweeping ‘glamorization’ of smart materials, we often forget the legacy from which these materials sprouted seemingly so recently and suddenly Texts from as early as

300 BC were the first to document the ‘science’ of alchemy.1 Metallurgy was by then a well-developed technology prac-ticed by the Greeks and Egyptians, but many philosophers were concerned that this empirical practice was not governed

by a satisfactory scientific theory Alchemy emerged as that theory, even though today we routinely think of alchemy as having been practiced by late medieval mystics and charla-tans Throughout most of its lifetime, alchemy was associated with the transmutation of metals, but was also substantially concerned with the ability to change the appearance, in particular the color, of given substances While we often hear about the quest for gold, there was an equal amount of attention devoted to trying to change the colors of various metals into purple, the color of royalty Nineteenth-century magic was similarly founded on the desire for something to be other than it is, and one of the most remarkable predecessors

to today’s color-changing materials was represented by an ingenious assembly known as a ‘blow book’ The magician

Materials in architecture and design 1

1 Materials in architecture and design

s Figure 1-1 NASA’s vision of a smart plane

that will use smart materials to ‘morph’ in

response to changing environmental

con-ditions (NASA LARC)

would flip through the pages of the book, demonstrating to the audience that all the pages were blank He would then blow on the pages with his warm breath, and reflip through the book, thrilling the audience with the sudden appearance

of images on every page That the book was composed of pages alternating between image and blank with carefully placed indentions to control which page flipped in relation to the others makes it no less a conceptual twin to the modern

‘thermochromic’ material

What, then, distinguishes ‘smart materials’? This book sets out to answer that question in the next eight chapters and, furthermore, to lay the groundwork for the assimilation and exploitation of this technological advancement within the design professions Unlike science-driven professions in which technologies are constantly in flux, many of the design professions, and particularly architecture, have seen relatively little technological and material change since the 19th century Automobiles are substantially unchanged from their forebear a century ago, and we still use the building framing systems developed during the Industrial Revolution In our forthcoming exploration of smart materials and new technol-ogies we must be ever-mindful of the unique challenges presented by our field, and cognizant of the fundamental roots of the barriers to implementation Architecture height-ens the issues brought about by the adoption of new technologies, for in contrast to many other fields in which the material choice ‘serves’ the problem at hand, materials and architecture have been inextricably linked throughout their history

1.1 Materials and architecture

The relationship between architecture and materials had been fairly straightforward until the Industrial Revolution Materials were chosen either pragmatically – for their utility and availability – or they were chosen formally – for their appearance and ornamental qualities Locally available stone formed foundations and walls, and high-quality marbles often appeared as thin veneers covering the rough construction Decisions about building and architecture determined the material choice, and as such, we can consider the pre-19th century use of materials in design to have been subordinate to issues in function and form Furthermore, materials were not standardized, so builders and architects were forced to rely on

an extrinsic understanding of their properties and perfor-mance In essence, knowledge of materials was gained through experience and observation Master builders were

Smart Materials and New Technologies

2 Materials in architecture and design

s Figure 1-2 Wireless body temperature

sen-sor will communicate soldier’s physical state

to a medic’s helmet (Courtesy of ORNL)