Mechanical performance of self-healing fiber-metal laminates under transverse loading

Nowadays, fiber-metal laminates (FMLs) have gained many applications in aviation, marine and automotive industries. These structures include thin metallic face sheets bonded to the composite prepregs. Internal damages in FMLs are difficult to detect and repair by conventional methods. To overcome this, in the present study a self-healing polymeric system based on chopped hollow glass tubes has been introduced and employed to recover the flexural strength of Al-2024/E-glass-epoxy/Al-2024 specimens after damage. The micro-tubes were located next to each other in pairs and filled with restorative agents (epoxy resin amine hardener). The aim of this study was to find a suitable volume fraction and also the optimum time to achieve the maximum healing efficiency. Various volume fractions of filled tubes containing 5, 8 and 11 vol.% healing agent together with different time passing period of 3 and 5 days after primary damage were employed. The results demonstrated that the maximum healing efficiency for flexural strength (89%) was observed for the specimen with 8 vol.% healing agent after passing 5 days from the time of damage creation