Analysis of out-of-plane bending in one-sided bonded repair

An un-supported cracked plate repaired with a reinforcement bonded on one side may experience a considerable out-of-plane bending, resulting mainly from the load-path eccentricity. A geometrically linear analysis is presented in this paper for the crack extension force after the application of a one-sided repair. It is found that although the stress intensity factor K for a one-sided repair is higher than in two-sided repairs where there is no bending present, the key feature is retained that K does not increase indefinitely with increasing crack length, but instead approaches asymptotically a finite upper-bound corresponding to the solution for a semi-infinite crack. An analytical expression is derived for this upper bound, which provides a conservative estimate suitable for design purposes and parametric studies. This analytical solution is shown to agree well with a fully three-dimensional finite element analysis. Strategies to minimize the detrimental effect of out-of-plane bending are briefly discussed. (C) 1998 Elsevier Science Ltd.