The technology of cold extrusion strengthening holes with split sleeve is widely used in aviation manufacturing

maintenance and other fields to improve the fatigue life of aircraft structural holes. The residual stress distribution and fatigue life of cold extrusion strengthened hole of split sleeve were studied by simulation analysis method. Firstly

based on the finite element software ABAQUS

a finite element model of extrusion strengthening of 7050 aluminum alloy components was established

and the simulation results under different extrusion amounts were obtained

and the accuracy of the model was analyzed. Secondly

based on the results of the strengthened model

the fatigue life of the strengthened hole was predicted by using the fatigue analysis software Fe-Safe. Finally

a fatigue test comparison between the unextruded hole and the extrusion-strengthened hole with split sleeve was carried out. The results show that the most reasonable residual stress distribution can be obtained when the designed extrusion amount is 4.0% – 4.5%. When the extrusion amount exceeds 4.5%

the maximum residual compressive stress at the extrusion end basically remains unchanged. After extrusion

the hole diameter changes in a saddle shape along the axial direction

and the hole wall metal flows out toward both ends of the hole. This strengthening process has obvious effect on the fatigue gain of holes

and the fatigue life of strengthened holes is about 10 times that of unreinforced holes.