Damage to composites is often hidden to the eye. Where a metal structure will show a “dent” or “ding” after being damaged, a composite structure may show no visible signs of damage, and yet may have delaminated plies or other damage within
Impact energy affects the visibility, as well as the severity, of damage in composite structures. High and medium energy impacts, while severe, are easy to detect. Low energy impacts can easily cause “hidden” damage.
There are a variety of non-destructive inspection techniques available to help determine the extent and degree of damage. Each has its own strengths and weaknesses, and more than one method may be needed to produce the exact damage assessment required. The following table provides a basic comparison between the non-destructive inspection techniques. 'A' indicates damage where the technique scores well, and 'C' indicates damage where the technique is not so good.
Published courtesy of Abaris Training Resources, Inc