A simple method to calculate the crack growth life of adhesively repaired aluminum panels

In this paper, a simple method is developed to predict the crack growth life of single-side repaired aluminum panels. The patches are considered to be made of glass/epoxy, boron/epoxy and graphite/epoxy composite materials. For this purpose, crack growth life of the repaired panels are calculated using two different approaches: (1) The crack growths along the panel thickness uniformly. In this simplified approach, crack-front line remains perpendicular to the plate surfaces during the crack propagation. (2) The crack growths along the panel thickness non-uniformly. In this approach, initial crack-front line changes to a curved shape according to the variation of stress intensity factor during the crack propagation (real crack-front shape). Then, a new simple method is developed based on a parametric study using both approaches. Using this simple method, it is not necessary to perform the complex crack growth analysis based on the real crack-front shape. Therefore, the results of 3D analysis using the first approach or 2D analysis similar to the three layers technique may be used to estimate the crack growth life of the repaired panels. The obtained results are verified with the available experimental results.