Delamination and fatigue crack growth behavior in Fiber Metal Laminates (Glare) under single overloads

• Ktip,ol is a key influences delamination c and rack growth behaviors of Glare.
• Kink is observed when Ktip,ol becomes bigger and exceeds a critical value.
• Crack growth rate after overload applied cannot return to its original level.

Delamination extension and fatigue crack growth behaviors under single overloads were investigated for GLARE 2-2/1-0.3 with fiber direction of 00/00. The results indicate that the stress intensity factor at the crack tip in metal layer while overload applied, Ktip,ol is a key controlling variable which influences fatigue crack growth and delamination behaviors. When Ktip,ol becomes bigger and exceeds a critical value, an obvious kink in the delamination shape is observed nearby the location of overload applied. Crack growth rate after application of overload could not return to its original level even the crack grows beyond the overload plastic zone. The reduction magnitude of the crack growth rate becomes bigger with the overload ratio (intrinsically Ktip,ol) increasing. These new results for the crack growth behavior have never been reported before, which can be well explained by the delamination extension behavior observed after overload applied.