Analysis of the adhesive damage for different patch shapes in bonded composite repair of aircraft structures

•The rectangular patch presents weak risk of adhesive damage.•The elliptical patch presents the optimal shape.•The trapezoidal patch shape must be avoided.

In this study, the adhesive damage in bonded composite repair of aircraft structures is analyzed using a three dimensional finite element method. Four different patch shapes were chosen to analyze the adhesive damage: rectangular, trapezoidal, circular and elliptical. The modified damage zone theory was implemented in the FE code to evaluate the adhesive damage. The obtained results show that the rectangular shape is beneficial for the repair durability but it presents a disadvantage for the repair efficiency. The elliptical patch is found the optimal whereas the trapezoidal patch represents the worst shape among the four types analyzed in this paper.