NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Harold Liebowitz is president of the National Academy of Engineering.
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The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. Harold Liebowitz are chairman and vice chairman, respectively, of the National Research Council.
This study by the National Materials Advisory Board and the Aeronautics and Space Engineering Board was conducted under Grant No. FAA-93-G-040 with the U.S. Department of Transportation.
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COMMITTEE ON NEW MATERIALS FOR ADVANCED CIVIL AIRCRAFT
JOHN A.S. GREEN (Chair),
Lockheed Martin Laboratories, Baltimore, Maryland
BERNARD BUDIANSKY,
Harvard University, Cambridge, Massachusetts
DAVID J. CHELLMAN,
Lockheed Martin Aeronautical Systems Company, Marietta, Georgia
LARRY P. CLARK,
Boeing Defense and Space Group, Seattle, Washington
JOHN W. GILLESPIE, JR.,
University of Delaware, Newark
CHARLES E. HARRIS,
NASA Langley Research Center, Hampton, Virginia
MURRAY H. KUPERMAN,
United Airlines Maintenance and Operations Center, San Francisco, California
PAUL A. LAGACE,
Massachusetts Institute of Technology, Cambridge
VICKI E. PANHUISE,
AlliedSignal Aerospace, Tempe, Arizona
KENNETH L. REIFSNIDER,
Virginia Polytechnic Institute and State University, Blacksburg
MICHAEL P. RENIERI,
McDonnell Douglas Aerospace, St. Louis, Missouri
EDGAR A. STARKE,
University of Virginia, Charlottesville
HERBERT J. WARDELL,
Gulfstream Aerospace, Savannah, Georgia
Aeronautics and Space Engineering Board Liaison Representative
C. JULIAN MAY,
Tech/Ops International, Inc., Kennesaw, Georgia
National Materials Advisory Board Staff
THOMAS E. MUNNS, Senior Program Officer
AIDA C. NEEL, Senior Project Assistant
JACK HUGHES, Research Associate
Aeronautics and Space Engineering Board Staff
ALAN C. ANGLEMAN, Senior Program Officer
National Materials Advisory Board
ROBERT A. LAUDISE (Chair),
AT&T Bell Laboratories, Murray Hill, New Jersey
G.J. (REZA) ABBASCHIAN,
University of Florida, Gainesville
JAN D. ACHENBACH,
Northwestern University, Evanston, Illinois
MICHAEL I. BASKES,
Sandia National Laboratories, Livermore, California
I. MELVIN BERNSTEIN,
Tufts University, Medford, Massachusetts
JOHN V. BUSCH,
IBIS Associates, Inc., Wellesley, Massachusetts
HARRY E. COOK,
University of Illinois, Urbana
EDWARD C. DOWLING,
Cyprus AMAX Minerals Company, Englewood, Colorado
ROBERT EAGAN,
Sandia National Laboratories, Albuquerque, New Mexico
ANTHONY G. EVANS,
Harvard University, Cambridge, Massachusetts
CAROLYN HANSSON,
University of Waterloo, Ontario, Canada
MICHAEL JAFFE,
Hoechst Celanese Research Division, Summit, New Jersey
LIONEL C. KIMERLING,
Massachusetts Institute of Technology, Cambridge
RICHARD S. MULLER,
University of California, Berkeley
ELSA REICHMANIS,
AT&T Bell Laboratories, Murray Hill, New Jersey
EDGAR A. STARKE,
University of Virginia, Charlottesville
KATHLEEN C. TAYLOR,
General Motors Corporation, Warren, Michigan
JAMES W. WAGNER,
The Johns Hopkins University, Baltimore, Maryland
JOSEPH G. WIRTH,
Raychem Corporation, Menlo Park, California
ROBERT E. SCHAFRIK, Director
Aeronautics and Space Engineering Board
JOHN D. WARNER (Chair),
The Boeing Company, Seattle, Washington
STEVEN AFTERGOOD,
Federation of American Scientists, Washington, D.C.
JOSEPH P. ALLEN,
Space Industries International, Inc., Washington, D.C.
GEORGE A. BEKEY,
University of Southern California, Los Angeles
GUION S. BLUFORD, JR.,
NYMA, Inc., Brook Park, Ohio
RAYMOND S. COLLADAY,
Martin Marietta Astronautics, Denver, Colorado
BARBARA C. CORN,
B.C. Consulting, Inc., Searcy, Arkansas
STEVEN M. DORFMAN,
Hughes Telecommunications and Space Company, General Motors Hughes Electronics, Los Angeles, California
DONALD C. FRASER,
Boston University, Boston, Massachusetts
DANIEL HASTINGS,
Massachusetts Institute of Technology, Cambridge
WILLIAM HEISER,
United States Air Force Academy, Colorado Springs, Colorado
BERNARD L. KOFF,
Pratt & Whitney, West Palm Beach, Florida
DONALD J. KUTYNA,
Loral Corporation, Colorado Springs, Colorado
JOHN M. LOGSDON,
George Washington University, Washington, D.C.
FRANK E. MARBLE,
California Institute of Technology, Pasadena
C. JULIAN MAY,
Tech/Ops International, Inc., Kennesaw, Georgia
BRADFORD W. PARKINSON,
Stanford University, Stanford, California
GRACE M. ROBERTSON,
Douglas Aircraft Company, Long Beach, California
JOANN C. CLAYTON, Staff Director
Acknowledgments
The recommendations and conclusions of this report are the insights of many people and organizations with whom the committee interacted. In particular, the efforts of the following individuals who presented detailed briefings to the committee are greatly appreciated: Douglas Cairns (manager, Advanced Composites Technology, Hercules) on innovative composite processing (processing/performance relationships); Robert Crowe (Defense Science Office, Advanced Research Projects Agency) on smart materials and structures; Robert Gog (technical representative, Lufthansa Airlines) on aircraft operations and maintenance; Gerald Janicki (director of Advanced Materials and Structures, McDonnell Douglas Aerospace-Transport Aircraft) on new materials applications for subsonic aircraft; Donald E. Larsen (Advanced Technology Division, Howmet Corporation) on net-shape investment cast titanium components for application in civil aircraft; J.A. Marceau (Materials Technology, Boeing Commercial Airplane Group) on service experience with current (aging) fleet; S.G. Sampath (FAA Technical Center) on aging aircraft issues related to current commercial fleet lessons learned; Brian W. Smith (program unit chief, Materials Technology, Boeing Commercial Airplane Group) on market driven materials development and engineering needs in materials and processes for commercial airplanes; Darrel Tenney (Materials Division) and James Starnes (Structures Division, NASA Langley Research Center) on new materials and structures projected for advanced subsonic aircraft.
The support and encouragement of the Federal Aviation Administration are greatly appreciated; the committee also thanks Pramode Bhaghat, Peter Shyprykevich, Joseph Soderquist, and Bill Wall who participated in numerous meetings.
The committee especially acknowledges the efforts of Thomas Munns, senior program officer for the National Materials Advisory Board, and Alan Angleman, senior program officer for the Aeronautics and Space Engineering Board, who maintained the continuity of the study and provided all necessary staff support. They were ably assisted by Aida Neel and Jack Hughes.
Preface
Turbulence is normally a term associated with flying. However, in the recent past, the airline industry seems to have experienced a great deal of turbulence on the ground as well. Airlines have been buffeted by a combination of forces following deregulation. First, there was the broad and lengthy recession, followed by numerous fare wars, the intense competition from newer airlines, and most recently, the concern over the safety of commuter flights. All these forces have seriously impacted the financial health of the airline industry as a whole. In fact, the competition has become so intense that some well-known airlines are now struggling for survival. This situation, in turn, has influenced the aircraft manufacturers who, in response, have adopted a pragmatic "no-frills" approach toward future design and manufacturing developments.
It is against this dynamic background that the Committee on New Materials for Advanced Civil Aircraft embarked on this study concerning the application of new materials in the next generation of subsonic transports on behalf of the Federal Aviation Administration. It is with considerable trepidation that one approaches a task of such complexity, attempting to project technical developments within the industry up to 15–20 years in the future, when even near-term materials and structures developments seem unpredictable. However, after extensive debate, the committee believes there are some clear paths along which technology will evolve. What is more difficult to predict in this turbulent era is the timing of these developments.
The committee was highly interactive, working best with lively debate and discussion. It brought together a good balance of industrial and academic expertise, along with government experience, particularly from the National Aeronautics and Space Administration. There was a balance on the committee between experts knowledgeable in advanced metallic materials and organic matrix composites. In addition, committee expertise covered the entire spectrum of materials use, from the innovation of new materials; to alloy and composite selection, fabrication, design and manufacturing; to in-service experience and nondestructive evaluation and maintenance. Experience related to smaller executive aircraft as well as large transports was also represented on the committee.
In addition to drawing upon their own sources of information, members of the committee elected to use a series of indepth, expert briefings to focus discussion on key areas of materials research, development, manufacturing, and application. In these briefings, aircraft manufacturing and maintenance experts, material and component suppliers, industry and government research leaders with both commercial and military experience, and materials and structures researchers helped formulate the recommendations and conclusions of this report. Their insights added greatly to the scope of this report.
The purpose of this study is to identify engineering issues related to the introduction of new materials and their expected effect on the life-cycle durability of next-generation commercial transports. The committee investigated the likely new materials and structural concepts for the next-generation commercial aircraft and the key factors influencing application decisions. Based on these predictions, the committee identified and analyzed the design, characterization, monitoring, and maintenance issues that appeared to be most critical for the introduction of advanced materials and structural concepts. The scope of this study did not include issues related to the High-Speed Civil Transport or the hot stages of turbine engines, although the ancillary components of engines that may become warm in application (e.g., thrust reversers) are included. Also considered outside the scope of the study were specific issues related to rotorcraft. Accordingly, the primary focus of the committee was defined as the identification of new materials and structures for the category of large subsonic transport aircraft; the general aviation category was also included where there were related problems or concerns.
It is now our belief that, despite the prevailing (and probably continuing) turbulence in the airline industry, this report should provide some insight into the evolution of advanced materials and processing technology on next-generation commercial aircraft. In doing so, it will provide information that can help to maintain a safe, efficient, and viable commercial fleet.
Comments or suggestions that readers of this report wish to make can be sent via Internet electronic mail to nmab@nas.edu or by FAX to the National Materials Advisory Board (202) 334-3718.
John A.S. Green, Chair
Committee on New Materials for Advanced Civil Aircraft
Tables and Figures
TABLES
2-1 |
Summary of Innovative Structural Concepts |
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2-2 |
Design and Manufacturing Issues in Advanced Metallic Fuselage Development |
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2-3 |
Design and Manufacturing Issues in Composite Wing Development |
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2-4 |
Design and Manufacturing Issues in Composite Fuselage Development |
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4-1 |
NASA Flight-Service Components |
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4-2 |
Advantages and Limitations of the RTM Process |
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7-1 |
Typical Airline Maintenance and Service Plan |
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7-2 |
Causes of Ground Damage to Aircraft |
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7-3 |
Most Common Causes of Composite Structure Damage to Aircraft |
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7-4 |
Causes of Service Damage to Composite Structure |
FIGURES
1-1 |
Past and projected trends in world air travel in revenue-passenger miles (RPM) |
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1-2 |
After-tax profits and losses (based on 1994 dollars) for U.S. scheduled airlines |
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1-3 |
Past and projected manufacturing of commercial transports |
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1-4 |
Breakdown of direct operating costs for two fuel-price estimates |
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1-5 |
Breakdown of total aircraft cost |
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II-1 |
Advanced materials on the Boeing 777 |
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2-1 |
Cost drivers for a composite fuselage |
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2-2 |
Structural design drivers for a composite fuselage |
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2-3 |
Emerging manufacturing technologies for composite fuselage structure |
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3-1 |
HIP castings applications—F-22 wing-to-body rib castings |
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3-2 |
SPF process |
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3-3 |
Two-sheet SPF/DB process |
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3-4 |
Four-sheet SPF/DB process |
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4-1 |
RTM process |
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4-2 |
RFI process |
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4-3 |
Mold assembly for double diaphragm forming |
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4-4 |
Schematic of diaphragm-forming autoclave |
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4-5 |
Composite pultrusion process |
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6-1 |
Methodology for predicting remaining strength in composites |
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7-1 |
Diagram of aircraft interfaces with servicing and other equipment |
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7-2 |
Bolted splice repair of a composite primary structure panel |
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8-1 |
Probability of detection simulations for ultrasonic detection of circular cracks at different depths below a component surface for two scanning plans |