JOINING OF COMPOSITE STRUCTURES 295 Double overlap Single overlap Scarf Double scarf Stepped lap Double-stepped lap Fig.9.2 Schematic illustration of several types of bonded joint. aluminum alloy fuselage component by the extensive use of bonded construction. The demonstrated weight-saving was about 15%,with a 20%saving in cost. Lap joints relying solely on adhesive bonding,although structurally very attractive,are not generally used by major aircraft manufacturers in primary structural applications(such as fuselage splice joints)because of concerns with long-term environmental durability.These concerns stem from some early poor service experience with the environmental durability of adhesive bonds,resulting from the use of inadequate pre-bonding surface treatments and ambient-curing adhesives.JOINING OF COMPOSITE STRUCTURES 295 Double overlap Single overlap Scarf Double scarf ~===---~====~::::.~ ..... ,/ Stepped lap ZZZZZZZZ-'--ZZZZ_ZZZZZ__'_=_~ Double-stepped lap Fig. 9.2 Schematic illustration of several types of bonded joint. aluminum alloy fuselage component by the extensive use of bonded construction. The demonstrated weight-saving was about 15%, with a 20% saving in cost. Lap joints relying solely on adhesive bonding, although structurally very attractive, are not generally used by major aircraft manufacturers in primary structural applications (such as fuselage splice joints) because of concerns with long-term environmental durability. These concerns stem from some early poor service experience with the environmental durability of adhesive bonds, resulting from the use of inadequate pre-bonding surface treatments and ambient-curing adhesives