Lifetime of aircraft alloy plates with cold expanded holes

The results of study of cold expansion holes and their diameters on stress distribution, fatigue crack nucleation and its growth under uniaxial loading of plates are presented. A series of fatigue tests were carried out using plates containing plain holes and cold expanded holes in aluminium D16chT alloy (Al 2024-T3). In all cases, the increase of plain and cold expanded hole diameter from 8 mm to 10 mm increases crack initiation lifetime with a length of c1 = 0.25 mm and 0.5 mm. With the increase of cold expansion degree, the relative fatigue lifetime of specimens with both diameters decreases for a crack to initiate with the length of 0.25 mm and increases for the crack to initiate with the length of 0.5 mm.