Effect of cold expansion and bolt clamping on fretting fatigue behavior of Al 2024-T3 in double shear lap joints

In this paper the fatigue behavior of double shear lap joints treated by cold expansion and bolt clamping has been investigated. Fatigue tests and numerical simulations were conducted to study the combined effect of cold expansion and bolt clamping on the fatigue life and failure mode. The results showed significant changes on the fatigue behavior of the double shear lap joints at different load ranges. Depending on the degree of cold expansion and clamping torque, both plain fatigue and fretting fatigue failures were observed. The optimum degree of cold expansion in conjunction with the clamping force differs from those reported for joints that were cold expanded only.

► Combination of cold expansion and clamping changes the fatigue behavior of joints.
► In clamped joints, increasing cold expansion level decreases fatigue life.
► In clamped joints with lower level of cold expansion failure mode is plain fatigue.
► Increasing cold expansion level alters failure mode for clamped joints.
► Optimum cold expansion level for joints without clamping differs from clamped ones.