Evaluation of Detail Fatigue Properties of Curved Aluminum Alloy Parts Prepared by Shot Peen Forming
WANG Feng1, ZENG Yuansong2, HU Guojie3, GAI Pengtao2, SHANG Jianqin2, ZHOU Wenlong3, FU Xuesong3
1. AVIC The First Aircraft Institute, Xi’an 710089, China;
2. AVIC Manufacturing Technology Institute, Beijing 100024, China;
3. Dalian University of Technology, Dalian 116024, China
The detail fatigue property of aluminum alloy curved panel formed by unilateral shot peen forming was studied. As the shot peen formed panel with curved shape, the detail fatigue performance of curved surface sample was evaluated based on SWT model. The local load-bearing stress and strain characteristics on surface of sample during fatigue process were analyzed by means of point cloud mapping modeling, finite element simulation and resistance strain gauge monitoring. The results show that: under the same condition of axial loading 180 MPa nominal stress, the peak stress of flat plate is 263 MPa, and the local peak stress of curved plate is close to 400 MPa. The DFR cut-off value (DFRcutoff) of original flat plate is 184.6 MPa; The DFRcutoff of curved sheet formed by unilateral shot peening is 182.4 MPa by direct measurement, and is 221.6 MPa by SWT model evaluation. The DFRcutoff value of shot peening flat plate (bilateral shot peening) is 241.4 MPa, which is slightly higher than the SWT model evaluation value (error less than 10%), because the work hardening effect is not considered in the SWT evaluation. Therefore, SWT model is an effective method to evaluate the detail fatigue performance of shot peened panel.