Experimental and numerical investigations on fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints

doi:10.1016/j.jmst.2017.09.020

Abstract

Abstract:

The fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints was studied by high-frequency fatigue test and finite element (FE) methods. The fatigue test results showed that a better enhancement of fatigue life was achieved for the joints with high-locked bolts by employing the combinations of cold expansion, interference fit, and clamping force. The fractography revealed that fatigue cracks propagated tortuously; more fatigue micro-cliffs, tearing ridges, lamellar structure were observed, and fatigue striation spacing was simultaneously reduced. The evaluation of residual stress conducted by FE methods confirmed the experimental results and locations of fatigue crack initiation. The extension of fatigue lives can be attributed to the evolution of fatigue damage and effect of beneficial compressive residual stresses around the hole, resulting in the delay of crack initiation, crack deflection, and plasticity-induced crack closure.

Key words: 7050 aluminum alloy, Bolted joint, Fatigue behavior, Finite element analysis, Residual stress

Xiaomei Liu, Hao Cui, Shangzhou Zhang, Haipo Liu, Gaofeng Liu, Shujun Li. Experimental and numerical investigations on fatigue behavior of aluminum alloy 7050-T7451 single lap four-bolted joints[J]. J. Mater. Sci. Technol., 2018, 34(7): 1205-1213.

Figures/Tables 13

Fig. 1. Dimensions (mm) of single lap four-bolted joints (a) and HST12 bolt (b), HSL756 bolt (c).

Table 1 Interference fit, cold expansion, clamping force, bolt types, and stress levels for fatigue test of different joints.

Joint number	Interference fit size (IF)	Cold expansion (CA)	Clamping force (CF)	Bolt type	Ultimate strength, σ_b (MPa)	Stress level
0230	-0.2%	0	24.54 KN	HST12	359.6	5-67%σ_b
0240	+1.4%	0	24.54 KN	HST12	367.0	5-67%σ_b
0270	+1.4%	1%	24.54 KN	HST12	352.2	5-67%σ_b
0250	+1.4%	0	32.72 KN	HSL756	300.1	5-67%σ_b
0280	+1.4%	1%	32.72 KN	HSL756	319.9	5-67%σ_b

Fig. 2. Mesh size of bolted joints.

Fig. 3. Effect of cold expansion, interference fit, clamping force, bolt types on S-N curves for fatigue test joints.

Fig. 4. Fatigue failure of the joints for maximum applied load equal to 30% of static tensile strength: (a) 0230 (3.97×104 cycles), (b) 0240 (3.6×104 cycles), (c) 0270 (7.37×104 cycles), (d) 0280 (8.78×104 cycles).

Fig. 5. Fatigue crack propagation paths of the joints for maximum applied load equal to 30% of static tensile strength: (a) 0230, (b) 0240, (c) 0270, (d) 0250, (e) 0280.

Fig. 6. Fractography of fatigue crack initiation (a) and final crack zone (b) of 0230 joint subjected to 30% of static tensile strength.

Fig. 7. Fractography of fatigue crack propagation of 0240 (a), 0270 (b), 0250 (c), 0280 (d) joints subjected to 30% of static tensile strength.

Fig. 8. Fatigue striation patterns of different joints subjected to 30% of static tensile strength: (a) 0230, (b) 0270, (c) 0250, (d) 0280.

Fig. 9. Maximum principal stresses created around the hole of the joints: (a) 0230, (b) 0240, (c) 0250, (d) 0270, (e) 0280.

Fig. 10. Circumferential residual stresses of the joints at entrance plane (a), middle plane (b), exit plane (c), and through thickness (d) subjected to cyclic load range of 2-20 kN.

Fig. 11. Radial residual stresses of the joints at entrance plane (a), middle plane (b), exit plane (c), and through thickness (d) subjected to cyclic load range of 2-20 kN.

Fig. 12. Average circumferential (a) and radial residual stress fields (b) of the joints subjected to cyclic load range of 2-20 kN.

References

[1]	A.M.P. de Jesus, A.L.L. da Silva, Correia J.A.F.O, J. Constr. Steel Res. 104(2015)81-90.
[2]	Y.H. Cho, T.S. Kim, Thin-Walled Struct. 101(2016) 43-57.
[3]	R.H. Oskouei, R.N. Ibrahim, Mater. Sci. Eng. A 528 (2011) 1527-1533.
[4]	H. Hüyük, O. Music, A. Koc?, C. Karado?gan, C? . Bayram, Proc.Eng. 81(2014)2030-2035.
[5]	M. Samaei, M. Zehsaz, T.N. Chakherlou, Eng. Fail. Anal. 59(2016) 253-268.
[6]	T. Liu, Q.D. Wang, Y.D. Sui, Q.G. Wang, J. Mater.Sci.Technol. 32(2016)298-304.
[7]	B. Mandal, A. Chakrabarti, Compos. Struct. 120(2015) 1-9.
[8]	T.N. Chakherlou, B. Abazadeh, Mater. Des. 37(2012) 128-136.
[9]	K.C. Viverosa, R.R. Ambriza, A. Amroucheb, A. Talhac, C. Garcíad, D. Jaramillo, J.Mater. Process.Technol. 214(2014) 2606-2616.
[10]	M. Yanishevsky, G. Li, G.Q. Shi, D. Backman, Eng. Fail. Anal. 30(2013) 74-90.
[11]	J.J. Warner, P.N. Clark, D.W. Hoeppner, Int. J. Fatigue 68 (2014) 209-216.
[12]	H.D. Gopalakrishna, H.N.Narasimha Murthy, M.Krishna, M.S. Vinod, A.V.Suresh, Eng. Fail. Anal. 17(2010) 361-368.
[13]	T.N. Chakherlou, M.J. Razavi, A.B. Aghdam, B. Abazadeh, Mater. Des. 32(2011)4641-4649.
[14]	N. Aleksandrova, Structures 6 (2016) 30-36.
[15]	J.C. Wei, G.Q. Jiao, P.R. Jia, T. Huang, Compos. Pt. B-Eng. 53(2013) 62-68.
[16]	J. Li, K.F. Zhang, Y. Li, P. Liu, J.J. Xia, Tribol. Int. 93(2016) 151-162.
[17]	J. Liu, J.X. Kang, W.Z. Yan, F.S. Wang, Z.F. Yue, Mater. Sci. Eng. A 527 (2010)3510-3514.
[18]	Y. Fu, E.D. Ge, H.H. Su, J.H. Xu, R.Z. Li, Chin J. Aeronaut. 28(2015) 961-973.
[19]	H. Taghizadeh, H. Ghorbani, A. Mohammadpour, Int. J. Mech. Sci. 90(2015)6-15.
[20]	H. Wu, J. Mater, Process. Technol. 212(2012) 1819-1824.
[21]	T.N. Chakherlou, B. Abazadeh, Mater. Des. 33(2012) 425-435.
[22]	T.N. Chakherlou, M. Shakouri, A. Akbari, A.B. Aghdam, Eng. Fail. Anal. 25(2012) 29-41.
[23]	Y. Sun, W.P. Hu, F. Shen, Q.C. Meng, Y.M. Xu, Int. J. Mech. Sci. 107(2016)188-200.
[24]	F. Esmaeili, T.N. Chakherlou, M. Zehsaz, Mater. Des. 59(2014)430-438.
[25]	C. Zhang, H. Li, M.Q. Li, J. Mater.Sci.Technol. 32(2016) 259-264.
[26]	X.L. Liu, Y.K. Gao, Y.T. Liu, D.F. Chen, J. Aeronaut Mater. 31(2011) 24-27.
[27]	M. Mirzajanzadeh, T.N. Chakherlou, J. Vogwell, Eng. Fract. Mech. 78(2011)1233-1246.
[28]	A. Benhamena, A. Talha, N. Benseddiq, A. Amrouche, G. Mesmacque, M.Benguediab, Mater. Sci. Eng. A 527 (2010) 6413-6421.
[29]	R.H. Oskouei, M. Keikhosravy, C. Soutis, Aero J. 114(2010) 315-320.