ABSTRACT
Internal damage caused by low velocity impact loading, such as hail, tool drops, and daily use, is a concern when evaluating the lifecycle of composite overlays used to repair or reinforce metallic structure. To investigate internal damage relative to external visible damage, inform inspection/maintenance, and provide validation data for future computational modeling, five configurations of composite/metal structure were experimentally tested by impact at two energy levels to cause low velocity impact damage. Plates were fabricated with an E-glass/epoxy or a carbon fiber/epoxy composite co-cured to an Aluminum 5456 substrate. In addition to collecting test data such as force/displacement and impact conditions, computerized tomography imaging was performed on the impacted plates to analyze the internal damage in 3D. Primary findings illustrate that both applied impact energies damaged all configurations and that the internal damage was more substantial than indicated by external (visible) damage.
