_STP_524-1973.pdf

APPLICATIONS OF COMPOSITE MATERIALS A S T M SPECIAL T E C H N I C A L P U B L I C A T I O N 524 Edited by Michael J.Salkind,Ph.D.Chief,Structures and i/iateriais Siiors/by A M E R I C A N S O C I E X Y E O R T E S T I N G A N D M A T E R I A L S 1973 Library of Congress Catalog Card Number:72-93841 NOTE The Society is not responsible,as a body,for the statements and opinions advanced in this publication.Printed in Tallahassee,Fla.February 1973 Copyright by ASTM Intl(all rights reserved);Sun Jan 3 21:45:08 EST 2016Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.Foreword The technology of high performance fiber composites has been with us for only one decade.Although fiberglass has been available for many years,the discovery of boron fiber in the early 1960s,followed quickly by graphite and other fibers,ushered in a new era of structural composites which included the rediscovery of fiberglass for critical,highly loaded structures.At the present time there are several hundred advanced composite structures which are flying,and the technology which was developed primarily for aerospace is being quickly adapted to commercial applications,including machinery,sporting equipment,and storage tanks,among others.The rapid developments in composite technology,which occurred primarily in the 1960s in the aerospace field,are chronicled in this book.Because this field is advancing rapidly,the material in this book is not completely up-to-date;however,it is still remarkably vaUd in providing a review of the fundamental technological base in this field.M.J.Salkind Stratford,Connecticut October 1972 Dedication To Dr.Isaac H.Schwartz my good friend and mentor M.J.Salkind Copyright by ASTM Intl(all rights reserved);Sun Jan 3 21:45:08 EST 2016Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.Related ASTM Publications Composite Materials:Testing and Design(Second Conference),STP 497(1972),$36.50 Composite Materials:Testing and Design,STP 460(1970),$31.00 Interfaces in Composites,STP 452(1969),$16.50 Copyright by ASTM Intl(all rights reserved);Sun Jan 3 21:45:08 EST 2016Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.Contents Chapter I Commercial Aircraft-R.R.JUNE AND J.R.LAGER 1 Chapter II Military Aircraft-L.E.HACKMAN 43 Chapter III VTOL Aircraft-M.J.SALKINU 76 Chapter IV HeUcopter Rotor Blades-R.L.PINCKNEY 108 Chapter V Space Structures-J.D.FOREST AND J.L.CHRISTIAN 134 Chapter VI Fabrication Processing-S.YURENKA ELLIOTT 163 Index 187 Copyright by ASTM Intl(all rights reserved);Sun Jan 3 21:45:08 EST 2016Downloaded/printed byUniversity of Washington(University of Washington)pursuant to License Agreement.No further reproductions authorized.R.R.June andJ.R.Lager Chapter I-Commercial Aircraft REFERENCE:June,R.R.and Lager,J.R.,Commercial Aircraft,Applications of Composite Materials,ASTM STP 524,American Society for Testing and Materials,1973,pp.142.ABSTRACT:The use of composite materials offers considerable potential for reducing structural weight and,therefore,increasing productivity of commercial aircraft.The application of composites must be performed selectively,as some structures offer considerable potential for cost effective use,whereas others are more cost effective as metal structures.Heavily loaded beams,columns,and stiffness critical control surfaces are at present the major areas of application of composite materials.KEY WORDS:composite materials,fiber composites,aircraft,composite struc-tures,cost effectiveness,boron,graphite,fiberglass reinforced plastics The aircraft industry has taken an intense interest in advanced fibrous reinforced composites.Proper use of these new materials offers the potential for reducing the weight of aircraft structural components by as much as 50 percent.Basic structural elements such as beams and columns offer the most potential for cost effective weight reduction.More complex components such as control surfaces,while advancing the state-of-the-art,offer less potential.An estimate of the potential weight reduction for a typical subsonic aircraft is shown in Fig.1.Although the estimated average structural component weight reduction of 20 percent seems conservative,it can affect a rather large percentage of the net airframe weight(50 percent)and results in a total estimated weight saving of 19 500 lb.The structural efficiency of advanced composites is exemplified by the fact that this weight saving is cost effective and is accomphshed through the use of only 9750 lb of composite material.For unidirectional loading,advanced composites offer a significant weight reduction with the added advantages of being relatively easy to fabricate,analyze,and design.Because of this,it is felt that initial commercial appUcations of advanced compos