Low-velocity impact performance and effect factor analysis of scarf-repaired composite laminates

Low-velocity impact performance of scarf-repaired composite laminates was investigated by experimental and numerical methods. The numerical model was built using continuum damage mechanics and cohesive elements were used in all the interfaces of the adherends (i.e. the patch and the parent). The model was verified to be efficient. Based on it, damage profiles and damage mechanism were studied, and the effects of the scarf angle, the adhesive thickness and the patch off-axis angles were analyzed. Results show that the patch damage occurs in its center region through the thickness, while the damages in the parent and adhesive mainly occur around the back face. Damage area of the patch is obviously more serious than that of the parent, and the adhesive can protect the parent to some degree. The scarf angle, the adhesive thickness and the patch off-axis angles have effects on the impact properties. The scarf angles ranging from 7° to 8°, the adhesive thicknesses of 0.15 mm, the patch off-axis angles ranging from 135° to 160° are recommended for better impact performances.