NEW MATERIALS FOR NEXT-GENERATION COMMERCIAL TRANSPORTS

Committee on New Materials for Advanced Civil Aircraft

National Materials Advisory Board

Aeronautics and Space Engineering Board

Commission on Engineering and Technical Systems

National Research Council

Publication NMAB-476


NATIONAL ACADEMY PRESS
Washington, D.C. 1996



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page R1
New Materials for Next-Generation Commercial Transports NEW MATERIALS FOR NEXT-GENERATION COMMERCIAL TRANSPORTS Committee on New Materials for Advanced Civil Aircraft National Materials Advisory Board Aeronautics and Space Engineering Board Commission on Engineering and Technical Systems National Research Council Publication NMAB-476 NATIONAL ACADEMY PRESS Washington, D.C. 1996

OCR for page R1
New Materials for Next-Generation Commercial Transports 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. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine. 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. Library of Congress Catalog Card Number 96-67749 International Standard Book Number 0-309-05390-0 Available in limited supply from: National Materials Advisory Board 2101 Constitution Avenue, NW HA-262 Washington, D.C. 20418 202-334-3505 Additional copies are available for sale from: National Academy Press 2101 Constitution Avenue, NW Box 285 Washington, D.C. 20055 800-624-6242 or 202-334-3313 (in the Washington metropolitan area) Copyright 1996 by the National Academy of Sciences. All rights reserved. Printed in the United States of America.

OCR for page R1
New Materials for Next-Generation Commercial Transports 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

OCR for page R1
New Materials for Next-Generation Commercial Transports 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

OCR for page R1
New Materials for Next-Generation Commercial Transports 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

OCR for page R1
New Materials for Next-Generation Commercial Transports This page in the original is blank.

OCR for page R1
New Materials for Next-Generation Commercial Transports 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.

OCR for page R1
New Materials for Next-Generation Commercial Transports This page in the original is blank.

OCR for page R1
New Materials for Next-Generation Commercial Transports 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

OCR for page R1
New Materials for Next-Generation Commercial Transports This page in the original is blank.

OCR for page R1
New Materials for Next-Generation Commercial Transports Contents EXECUTIVE SUMMARY   1 I. INTRODUCTION     1   REQUIREMENTS AND DRIVERS   7     Background   7     Industry Overview and Important Trends   7     Next-Generation Aircraft   8     Application of New Materials   9 II. MATERIALS, PROCESSES, AND STRUCTURAL CONCEPTS     2   STRUCTURAL CONCEPTS   15     Innovative Structural Concepts   15     Advanced Metallic Fuselage   21     Composite Wing   21     Composite Fuselage   22     Summary   24 3   METALLIC MATERIALS AND PROCESSES   26     Aluminum Alloys   26     High-Strength Steels   28     Titanium Alloys   28     Metal-Matrix Composites   30     Trends in Processing   31     Summary   35 4   POLYMERIC COMPOSITE MATERIALS AND PROCESSES   36     Composite Materials Development   37     Trends in Processing   38     Summary   44 5   ENVIRONMENTALLY COMPLIANT MATERIALS AND PROCESSES   45     Environmental Regulations   45     Workplace Health and Safety   45     Effect on Aircraft Materials   46     Summary   47 III. ANALYTICAL METHODS     6   METHODOLOGIES FOR ASSESSMENT OF STRUCTURAL PERFORMANCE   51     Analytical Prediction Methodology for Structural Integrity   51     Advanced Cost and Structural Optimization Methodology   55     Summary   55

OCR for page R1
New Materials for Next-Generation Commercial Transports IV. AIRCRAFT OPERATIONS     7   AIRCRAFT MAINTENANCE AND REPAIR   59     Airline Maintenance   59     Service Experience   60     Summary   65 8   NONDESTRUCTIVE EVALUATION   67     Thermal Methods   68     Acoustic Emission   68     Laser NDE Methods   69     Other NDE Methods   69     NDE as an Engineering Tool   69     Summary   70 V. CONCLUSIONS AND RECOMMENDATIONS     9   COMMITTEE FINDINGS   73     Conclusions   73     Organizational Roles   74     Recommendations   74 REFERENCES   77 APPENDIX: Biographical Sketches of Committee Members   83

OCR for page R1
New Materials for Next-Generation Commercial Transports Tables and Figures TABLES 2-1   Summary of Innovative Structural Concepts   16 2-2   Design and Manufacturing Issues in Advanced Metallic Fuselage Development   21 2-3   Design and Manufacturing Issues in Composite Wing Development   22 2-4   Design and Manufacturing Issues in Composite Fuselage Development   24 4-1   NASA Flight-Service Components   36 4-2   Advantages and Limitations of the RTM Process   39 7-1   Typical Airline Maintenance and Service Plan   60 7-2   Causes of Ground Damage to Aircraft   61 7-3   Most Common Causes of Composite Structure Damage to Aircraft   64 7-4   Causes of Service Damage to Composite Structure   65 FIGURES 1-1   Past and projected trends in world air travel in revenue-passenger miles (RPM)   8 1-2   After-tax profits and losses (based on 1994 dollars) for U.S. scheduled airlines   8 1-3   Past and projected manufacturing of commercial transports   9 1-4   Breakdown of direct operating costs for two fuel-price estimates   9 1-5   Breakdown of total aircraft cost   10 II-1   Advanced materials on the Boeing 777   13 2-1   Cost drivers for a composite fuselage   22 2-2   Structural design drivers for a composite fuselage   23 2-3   Emerging manufacturing technologies for composite fuselage structure   23 3-1   HIP castings applications—F-22 wing-to-body rib castings   33 3-2   SPF process   34 3-3   Two-sheet SPF/DB process   34 3-4   Four-sheet SPF/DB process   35 4-1   RTM process   39 4-2   RFI process   40 4-3   Mold assembly for double diaphragm forming   41 4-4   Schematic of diaphragm-forming autoclave   42 4-5   Composite pultrusion process   42 6-1   Methodology for predicting remaining strength in composites   54 7-1   Diagram of aircraft interfaces with servicing and other equipment   61 7-2   Bolted splice repair of a composite primary structure panel   66 8-1   Probability of detection simulations for ultrasonic detection of circular cracks at different depths below a component surface for two scanning plans   70

OCR for page R1
New Materials for Next-Generation Commercial Transports This page in the original is blank.