Application of the acoustic-emission and strain-gaging methods to testing of the residual strength of airplanes

The use of acoustic-emission (AE), optical, and strain-gaging methods in cyclic tests of an airplane has been considered. During tests, before the failure of an airplane, three zones were inspected. For this purpose, saw cuts were made in the lower planes of the left and right wings and in the load-carrying structure on the right side. The AE method allowed detection of growing flaws at a 10% load relative to the rated load, when the length of a fatigue crack was at most 1 mm and was not detected via the optical method.