Abstract: Based on the three-dimensional Hashin criterion and with the help of finite element method (FEM), a two-sided patching repair model of composite laminates was established. A patching model with damaged part removed but without the adhesive layer is introduced. Residual strength of the mother plate with and without patch are compared, and the damage process and the best patching angle of double-sided patching repair are also obtained. The results show that the recovery rate of tensile strength with double-side patch is between 50% and 80%, which can achieve the same repair effect as that of single-sided patching through a smaller patching area, which means less damage to the main plate and more applicable scenarios. The repair effect of double-sided patching first increases and then decreases with the increase of patching angle. When the patching angle is 6°, the repair effect is the best, and the strength recovery rate reaches 78%. The main plate and patch material for experimental verification are prepared from T300/7901 material. The failure load of the test specimen shows good agreement with the FEM results, and the relative error is less than 15%, which can prove the correctness of the modeling.

Key words: composite laminate, finite element method, double-sided patching, load-carrying performance