Studies of the Fracture Process in Composite Structural Elements Based on Strain Measurements and the Acoustic-Emission Technique

The results of cyclic tests of structural elements (SEs) with a stringer, which are made of the composite material (CM) Organit-IOT and are parts of an aileron from an C-80FH aircraft, are considered. As SEs are broken, information is obtained simultaneously from acoustic-emission (AE) and tensometric equipment and measurements of the fatigue crack's opening are carried out. An insignificant increase (by 0.25 mm) of the crack opening generates a considerable flow of AE signals. These signals are processed using cluster analysis, which makes it possible to separate the signals emitted by a propagating fatigue crack in the stringer region from the signals arriving from the region of the fracturing gripping jaw.