On the Characterization of Fatigue Crack Growth in a Plate With a Single-Sided Repair

Abstract

An unsupported cracked plate repaired with a reinforcement bonded on one side may experience considerable out-of-plane bending due to the load-path eccentricity. This out-of-plane bending causes the stress intensity factor at the crack tip to vary significantly through the plate’s thickness with a maximum value attained at the un-patched side of the crack. Even though significant analytical work has been done in the past to evaluate these thickness-varying stress intensity factors, however, to the authors’ knowledge, little work has been done to characterize the fatigue crack growth in a plate with a single-sided repair. The purposes of the present work are to (i) assess the accuracy of the available analytical methods for predicting the stress intensity factors of the panels with a single-sided repair and more importantly, and (ii) characterize the fatigue crack growth in these panels, using test results generated recently under the Composite Repair of Aircraft Structures (CRAS) program.