INVESTIGATION OF A CRACKED THICK ALUMINUM PANEL REPAIRED WITH A BONDED COMPOSITE PATCH

Abstract An experimental investigation was conducted to characterize the post-repair fatigue crack growth behavior in 6.350 mm thick 2024-T3 aluminum panels repaired with the asymmetrically bonded full width boron/epoxy composite patch. Three patch lengths and two patch-to-panel stiffness ratios were examined. Repairs were found to provide at least a four to five times improvement in the fatigue life over the unrepaired baseline (cracked) specimens. The effects of various parameters of the patch repair on fatigue crack growth rate behavior, thermally induced curvature due to the one-sided bonded repair of the thick panel, debond characteristics and fatigue life were characterized. Also, these characteristics of a repaired thick panel (6.35 mm) were compared with those of the repaired thin panel (3.175 mm).