Fatigue Crack Detection in Coldworked Aluminum Alloys Using Acoustic Emission Technique

Abstract

Fractures of mechanical components and structures are often produced by initiation and propagation of fatigue cracks. Especially, in the case of aircrafts, since fatigue failure generally was caused by an invisible small crack, it is necessary to detect an initial crack during in-service inspection. The purpose of this research is to identify and recommend methods of inspection that would provide timely detection of fatigue failures. In this paper, acoustic emission (AE) technique has been used to detect fatigue crack. Acoustic emission technique is very useful to prevent catastrophic failure of large scale structures with unknown discontinuities such as fatigue crack. This research is focused on the capability of AE technique to provide diagnostic information to detect fatigue crack growth and initiation under cyclic loading. The coldworked 2024-T351 and 7050-T7451 aluminum alloys are used for this study and these alloys usually applied in aircraft primary members.

Finite element parametric study of the split sleeve cold expansion on residual stresses and pulling force

“…The Aluminum 2024-T351 is chosen for the workpiece material, and three levels of Al 2024-T351's yield strength were obtained from the open publications. [33][34][35] Figure 3 presents the stress-strain curves of these three Al 2024-T351 workpieces. Three levels of the applied expansion percentage are drawn from the SSCE process tolerance margins.…”