A self-validating adhesive system is proposed in which 'zero volume unbonds
' or 'kissing' bonds, which are undetectable by NDE techniques, may be fill
ed and bonded by a secondary component in the adhesive during cure. The sys
tem shows the principal criteria required for such a smart system, and has
been shown to enhance the strength of a bonded joint without undue deterior
ation in durability or water uptake. Crown copyright (C) 2000 Published by
Elsevier Science Ltd. All rights reserved.