What type of hole defect is characterized by peeled back and uncut fiber fragments around the drilled hole?

The type of hole defect characterized by peeled back and uncut fiber fragments around the drilled hole is referred to as fiber breakout. This condition occurs during the drilling process of composite materials, where the cutting action fails to cleanly sever the fibers, resulting in a rough, jagged edge around the hole. Instead of a clean hole, the fibers appear to have lifted away from the matrix material, leading to a distinctive appearance of fragmented fibers at the periphery.

This defect can significantly affect the structural integrity of the component, as proper fiber alignment and adhesion is crucial in composite materials for maintaining strength and durability. Understanding how to identify and differentiate fiber breakout helps mechanics assess the quality of drilled holes in composites and apply appropriate repair or mitigation techniques if necessary.

Other terms like delamination, chipping, and fraying refer to different defects that arise from various issues during machining or handling of composite materials, but they do not specifically describe the phenomenon of peeled fibers around a drilled hole. Delamination pertains to layers separating, chipping involves small pieces being removed from the edge, and fraying refers to the unraveling of fibers along a cut edge, none of which accurately capture the characteristic of fiber breakout.