The three-dimensional finite element model of foam core sandwich panel with penetrating defects is established.Finite element analysis is carried out on this model under the uniaxial and twin-axial tensile loading.According to the stress distributions of material principle direction of the scarf-patch repaired panel,the uniaxial and twin-axial tensile strength of the intact and scarf-patch repaired panels are calculated based on the strength criterion of maximum stress.It is shown that under the uniaxial tensile loading,the strength recovery coefficient of the repaired panel is 88.1%,and the initial damage mode is matrix shear failure.Under the twin-axial tensile loading,the strength recovery coefficient of the repaired panel is 97.6%,and the initial damage mode is the fracture of the reinforcing fiber.The optimum number of surface patch is one or two.More surface patches cause local stress concentration and thus strength reduction of the panel occurs.