<p>The repaired sandwich specimens were fabricated with an upper facesheet, a Nomex core, and a lower facesheet, which were then tested to characterize the failure behavior. At first, the specimens were tested under static loading to the maximum load of 7.75 to 10.17 kN. Then, the maximum fatigue amplitude was selected at 90% of 10.17 kN and gradually reduced until the fatigue cycles greater than 60,000 reached. This was defined as an endurance limit. During static testing, four strain gauges were attached to the repaired section and the strain values were used to analyze the failure behavior. The S₁ strain and the applied load were used to estimate the elastic modulus with a mean of 53.74 MPa of the upper facesheet. By analyzing the failure behavior, two critical failure points (A and B) were observed where the maximum bending moment was applied to the repaired section under static and fatigue loadings. The progressive failure analysis under static loading confirmed that the failure occurred due to weft tow splitting, matrix cracking, and warp tow rupturing. A similar analysis was carried out to characterize the fatigue failure behavior. The excessive matrix cracking was observed at critical points A and B before the failure of the facing sheet occurred. At the mesoscale, matrix cracking and intra-tow splitting were observed before facing sheet failure. SEM images show rough and cusp-like failure features due to fatigue loading, which is different from the smoother failure surfaces by static loading.</p>