Fatigue crack growth study of CFRP patch repaired Al 2014-T6 panel having an inclined center crack using FEA and DIC

• In single sided repair one sided patch causes additional bending and mode mixity.
• In single sided repair non-uniform crack growth profile is observed.
• Adhesive interface modeled as cohesive zone using contact elements.
• Double sided repair offered maximum reduction in SIF and higher fatigue life.
• DIC is found out to be a suitable technique to monitor crack growth accurately.

In this work, the fatigue life of unrepaired and repaired Al-2014-T6 panels with an inclined center crack is investigated. Cracked panels are repaired through single- and double-sided adhesively bonded carbon fiber reinforced polymer (CFRP) patch. The fatigue crack growth is monitored experimentally using digital image correlation and numerically using 3D finite element analysis. The adhesive-interface between the panel and patch is modeled using bilinear cohesive law. The CFRP/Al-2014-T6 adhesive-interface properties are obtained from the baseline tests. Fatigue life of double-sided repaired panel is observed to be twice that of single-sided. And non-uniform crack front is observed in single-sided repaired panels.