The largest source of damage to a commercial aircraft is caused by accidental contact with ground service equipment (GSE). The cylindrical bumper typically found on GSE distributes the impact load over a large contact area, possibly spanning multiple internal structural elements, which can lead to widespread damage that is difficult to visually detect, particularly for resilient composite fuselage skin. To better understand internal damage formation versus visual detectability, stiffened composite panels of various size and complexity have been tested at UCSD's Powell Labs.
The experimental observations have established that visual detectability is dependent on the impact location and immediately-adjacent internal structure of the panel, as well as the impactor geometry and total deformation of the panel. In parallel to the experiments, modeling capability to predict blunt impact damage is being established. This research is funded by the Federal Aviation Administration.