Abstract: Patch repairis a technologically simple and extensively employed composite structure repair technology. Tensile experiments on the composite laminate for experimental purpose with through-hole damage after single side patch repair is conducted. During the experiments, a research on how the diameter of patch influence the effectiveness of single side patch repair by changing patches′ diameters while keeping their ply stacking sequence and thickness constant is accomplished as well as an analysis of its failure mechanism based on the strain data of laminates at corresponding places collected during the experiment and the load-displacement curve on the basis of the data. The results show that the recovery rate of failure strength of test pieces after single-side patch repair is about 34% to 50%, and bonded repair has a recovery effect on the stiffness of laminates with through-hole damage. The longer the patch diameter, the higher the recovery rate of failure strength. When the patch diameter is relatively short, the adhesive fails before parent laminate. Hence, the repair effect is not obvious under this circumstance. When it increases to a certain extent, the strength of the adhesive is higher than parent laminate. At this time, patch repair can help increase the tensile strength of the damaged specimen. A finite element model is established based on the experiments, which can effectively predict failure modes and tensile strength of the test pieceand analyze its stress distribution. By changing the parameters of the model, a study on the relationship between patch sizes and damage apertures providing best repair effect is conducted. The results show that high repair efficiency can be obtained when the patch diameter is 30 mm~40 mm longer than the damage aperture. This paper provides references for composite laminates patch repair plan design.

Key words: patch repair, composite laminate, tensile behavior, recovery of failure strength, finite element model