Control of crack propagation in metals by the use of composites

Fatigue crack propagation in aluminium alloys has been controlled by the use of adhesively bonded carbon reinforced epoxy patches. Fatigue cracks were grown in single-edge-notched specimens under oscillating tension and procured CFRP patches were adhesively bonded in front of the crack tip. The patched specimens were again subjected to fatigue. The application of the patch stopped the cracks from further propagation. A number of microcracks nucleated near the crack tip and one of them became a macrocrack and propagated across the specimen. The residual fatigue life of the cracked specimens was increased by a factor of 10