Effects of aluminum alloy plate thickness on single-sided repair efficiency for boron fiber/epoxy composites

Taking vacuum pack techniques for patches of boron fiber/epoxy (B_f/epoxy) composites，this study tested thermal properties and quasi-static mechanics properties of the single-sided repaired aluminum alloy plate of different thickness with a cent ral crack in it . It analyzed the residual thermal strain and stress intensity factor (SIF) of the repair specimen by using a 3D finite element model，The results show that the bending deflection of the repair specimen decreases with the increase of the plate thickness. The residual thermal strain at the crack tip of the lower plate surface increases with the increase of the plate thickness，and the residual thermal strain of the upper patch surface increases with the decrease of plate thickness , which conformed well to the finite element analysis results.SIF of the aluminum alloy plate with central crack decreases with the increase of plate thickness，while the SIF of the single-sided repair specimen increases with the increase of plate thickness. Af ter the patches of unidirectional B_f/epoxy composites of the same length and width was repaired , the retention rate of bearing capacity for the repair specimen of 1. 76mm thick plate is 93. 85 % while for the plate of 10. 20 mm it is only 84. 01 %. The stiffness of the repair specimen is reactivated and the equivalent stiffness is larger than that of the no-flaw specimen.