Numerical Simulation Investigation on Split Sleeve Cold Expansion of Ti-Al Stacked Structure

Abstract

Split sleeve cold expansion (SSCX) can effectively enhance fatigue life of holes by improving the field of residual stress. Numerical simulations were conducted to investigate the parameter influence mechanism and obtain higher compressive residual stress (CRS). Expansion method, degree of cold expansion (DCE), friction coefficient between laminations and depth-diameter ratio were analyzed. For Ti-Al stacked joint holes, two expansion methods are proposed, namely aluminum alloy first followed titanium alloy (Al first) and titanium alloy first followed aluminum alloy (Ti first). The results show that expansion method and DCE have significant effects on the field of circumferential residual stress, and the friction has a negligible influence. A higher value of CRS and a wider layer of plastic deformation are induced with Ti first. Optimal DCE of Ti-Al stacked structure is 5.2%–5.6%. As the depth-diameter ratio is in the range of 0.5–1.25, a positive linear correlation between the maximum compressive residual stress (CRS_max) and depth-diameter ratio is shown.

Keywords

Ti-Al stacked structure / SSCX / residual stress / expansion method / DCE

References

[1] Fu Y C, Ge E D, Su H H, et al. Cold Expansion Technology of Connection Holes in Aircraft Structures: A Review and Prospect[J]. Chin. J. Aeronaut., 2015, 28(4): 961-973.

[2] Lu S H, Gao Y, Li D C. Research Progress of Split Sleeve Cold Expansion Strengthening Technology[J]. Forging & Stamping Technol., 2021, 46(01): 1-9.

[3] Kang J D, Johnson W S, David A C. Three-Dimensional Finite Element Analysis of the Cold Expansion of Fastener Holes in Two Aluminum Alloys[J]. J. Eng. Mater. Technol-Trans. ASME, 2002, 124: 140-145.

[4] Burlat M, Julien D, Lévesque M, et al. Effect of Local Cold Working on the Fatigue Life of 7475-T7351 Aluminium Alloy Hole Specimens[J]. Eng. Fract. Mech., 2008, 75(8): 2042-2061.

[5] Achard V, Daidie A, Paredes M, et al. Optimization of the Cold Expansion Process for Titanium Holes[J]. Adv. Eng. Mater., 2016, 19(6): 1 500 626

[6] Faghih S, Shaha S K, Behravesh S B, et al. Split Sleeve Cold Expansion of AZ31B Sheet: Microstructure, Texture and Residual Stress[J]. Mater. Des., 2020, 186: 108 213.

[7] Cheol K, Dae-Jin K B, Chang-Sung S, et al. Finite Element Analysis of the Residual Stress by Cold Expansion Method Under the Influence of Adjacent Holes[J]. J. Mater. Process. Technol., 2004, 153–154: 986-991.

[8] Liu Y S, Shao X J, Liu J, et al. Finite Element Method and Experimental Investigation on the Residual Stress Fields and Fatigue Performance of Cold Expansion Hole[J]. Mater. Des., 2010, 31(3): 1208-1215.

[9] Maximov J T, Duncheva G V, Ganev N, et al. Modeling of Residual Stress Distribution Around Fastener Holes in Thin Plates after Symmetric Cold Expansion[J]. J. Braz. Soc. Mech. Sci. Eng., 2014, 36(2): 355-369.

[10] Liu J, Shao X J, Liu Y S, et al. Effect of Cold Expansion on Fatigue Performance of Open Holes[J]. Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct Process, 2008, 477(1–2): 271-276.

[11] Seifi R. Total Fatigue Lives, Crack Growth Paths and Cycles in Cold Expanded Adjacent Holes[J]. Int. J. Fatigue, 2018, 113: 69-77.

[12] Hou S, Zhu Y L, Cai Z H, et al. Effect of Hole Cold Expansion on Fatigue Performance of Corroded 7B04-T6 Aluminium Alloy[J]. Int. J. Fatigue, 2019, 126: 210-220.

[13] Ayatollahi M R, Arian Nik M. Edge Distance Effects on Residual Stress Distribution Around a Cold Expanded Hole in Al 2024 Alloy[J]. Comput. Mater. Sci., 2009, 45(4): 1134-1141.

[14] Yang H J, Chen Y, Xu J H, et al. Experimental Research on Low Frequency Vibration—Assisted Hole Making of Ti/Al Stacked Structure[J]. Aeron. Manuf. Technol., 2017(Z1): 16–21

[15] Liu K, Li J F, Sun J, et al. Investigation on Chip Morphology and Properties in Drilling Aluminum and Titanium Stack with Double Cone Drill[J]. Int. J. Adv. Manuf. Technol., 2018, 94(5): 1947-1956.

[16] Zhu Z, Liu K, Sun J, et al. Investigation on Performance Characteristics and Metallographic Transformation on Drilling Aluminium/Titanium Sandwich[J]. J. Sandw. Struct. Mater., 2017, 21(4): 1578-1594.

[17] Yuan X, Yue Z F, Wen S F, et al. Numerical and Experimental Investigation of the Cold Expansion Process with Split Sleeve in Titanium Alloy TC4[J]. Int. J. Fatigue, 2015, 77: 78-85.

[18] Mahendra Babu NC, Jagadish T, Ramachandra K, et al. A Simplified 3-D Finite Element Simulation of Cold Expansion of a Circular Hole to Capture through Thickness Variation of Residual Stresses[J]. Eng. Fail. Anal., 2008, 15(4): 339-348.

[19] Shahriary P, Chakherlou T N. Investigating the Effect of Cold Expansion on Frictional Force Evolution during Fretting Fatigue Tests of AL2024-T3 Plates[J]. Int. J. Mech. Sci., 2018, 135: 146-157.

[20] Liu K Y, Zhou L, Yang X S, et al. Finite Element Simulation of the Cold Expansion Process with Split Sleeve in 7075 Aluminum Alloy[J]. J. Inst. Eng. India Ser. C, 2021, 102(2): 1-1.