Damage Tolerance

Damage tolerance was defined in the 1970s for civil aircraft structures. Impact damage tolerance in composite structures depends on two main phenomena: the loss of strength caused by the impact; and the detectability of the impact. This chapter discusses what impact damage looks like and how this damage develops to lead to the final fracture during compression after impact (CAI). It then focuses on the criteria used to size a composite in the context of impact damage tolerance. The complexity of these sizing cases arises from the fact that both the impact damage, or more specifically the structure's loss of residual strength due to the impact and its detectability, or more exactly the permanent indentation left by the impact, must be considered simultaneously.