CHARACTERIZATION OF FATIGUE-CRACK GROWTH IN ALUMINUM PANELS WITH A BONDED COMPOSITE PATCH

This study introduces an analytical procedure to characterize the fati gue crack growth behavior in an aluminium panel repaired with a bonded composite patch. This procedure involves the computation of the stres s intensity factor from a two-dimensional finite element method consis ting of three layers to model cracked plate, adhesive and composite pa tch. In this three layer finite element analysis, as recently introduc ed by the authors, two-dimensional Mindlin plate elements with transve rse shear deformation capability are used. The computed stress intensi ty factor is then compared with the experimental counterpart. The latt er was obtained from the measured fatigue crack growth rate of an alum inium panel with a bonded patch by using the power law relationship (P aris Law) of an unpatched aluminum panel. Both a completely bonded pat ch (with no debond) and a partially bonded patch (with debond) are inv estigated in this study. This procedure, thus, provides an effective a nd reliable technique to predict the fatigue life of a repaired struct ure with a bonded patch, or alternatively, it can be used to design th e bonded composite patch configuration to enhance the fatigue life of cracked structure. (C) 1997 Elsevier Science Ltd.