A FEM-DBEM Investigation of the Influence of Process Parameters on Crack Growth in Aluminum Friction Stir Welded Butt Joints


Article Preview

Medium to high strength aluminum alloys, such as 2xxx, 6xxx, and 7xxx series, are actually considered of great interest in the transport industries. For aeronautical applications, the precipitation hardenable AA2024 (Al-Cu) alloy is gaining considerable attention, in particular for the realization of nose barrier beam or fuselage panels. In this context, remarkable research effort is currently focused on the application of the Friction Stir Welding (FSW) process, as a suitable alternative to fusion welding processes. The interest in aeronautical application of FSW process is also justified by the reduction of production costs and weight and by the increase of strength and damage tolerance with respect to riveted lap joints. The implementation of the technique in safety-critical components, however, requires a deeper understanding of static strength as well as of fatigue behavior of FSWed assemblies. In this sense some experimental results have already been presented in the inherent literature, relatively, for instance, to AA6082-T6 and AA6061-T6, AA6063-T6, AA2024-T351, AA2024-T8 alloys processed by FSW. Despite the unavoidable relevance of experimental testing, a numerical approach able to predict the mechanical behavior of FSWed assemblies is very desirable, in order to achieve time and cost compression and to implement computational optimization procedures. This paper deals with a numerical investigation on the influence of FSW process parameters, namely the rotating speed and the welding speed, on fatigue crack growth in AA2024-T3 butt joints. The computational approach is based on a combined Finite Element Method (FEM) and Dual Boundary Element Method (DBEM) procedure, in order to take advantage of the main capabilities of the two methods. In particular, linear elastic FE simulations have been performed to evaluate the process induced residual stresses, by means of a recently developed technique named contour method. The computed residual stress field has then been superimposed to the stress field produced by an applied fatigue traction load in a Dual Boundary Element Method (DBEM) environment, where the simulation of a crack, initiated and propagating along the previously mentioned cutting line, can be performed in an automatic way. A two-parameters crack growth law is used for the crack propagation rate assessment. The DBEM code BEASY and the FEM code ANSYS have been sequentially coupled in the aforementioned numerical approach by using a BEASY interface module and in house developed routines. Computational results have been compared with experimental data, showing a satisfactory agreement. The influence of process parameters on the residual stresses distribution has also been highlighted.



Key Engineering Materials (Volumes 554-557)

Edited by:

Ricardo Alves de Sousa and Robertt Valente




R. G. Citarella et al., "A FEM-DBEM Investigation of the Influence of Process Parameters on Crack Growth in Aluminum Friction Stir Welded Butt Joints", Key Engineering Materials, Vols. 554-557, pp. 2118-2126, 2013

Online since:

June 2013




[1] M. Guerra, C. Schmidt, J.C. McClure, L.E. Murr, A.C. Nunes, Flow patterns during friction stir welding, Mater. Charact. 49 (2003) 95-101.

DOI: https://doi.org/10.1016/s1044-5803(02)00362-5

[2] H.N.B. Schmidt, T.L. Dickerson, J.H. Hattel, Material flow in butt friction stir welds in AA2024-T3, Acta Mater. 54 (2006), 1199–1209.

DOI: https://doi.org/10.1016/j.actamat.2005.10.052

[3] M.A. Sutton, B. Yang, A.P. Reynolds, R. Taylor, Microstructural studies of friction stir welds in 2024-T3 aluminum, Mater. Sci. Eng. A-Struct. 323 (2002), 160-166.

DOI: https://doi.org/10.1016/s0921-5093(01)01358-2

[4] B. Yang, J. Yan, M.A. Sutton, A.P. Reynolds, Banded microstructure in AA2024-T351 and AA2524-T351aluminum friction stir welds Part I. Metallurgical studies, Mat. Sci. and Eng. A-Struct 364 (2004), 55–65.

DOI: https://doi.org/10.1016/s0921-5093(03)00532-x

[5] S.A. Khodir, T. Shibayanagi, Friction stir welding of dissimilar AA2024 and AA7075 aluminum alloys, Mat. Sci. Eng. B-Adv. 148 (2008), 82–87.

DOI: https://doi.org/10.1016/j.mseb.2007.09.024

[6] H.J. Liu, H. Fujii, M. Maeda, K. Nogi, Tensile properties and fracture locations of friction-stir-welded joints of 2017-T351 aluminum alloy, J. Mater. Process. Tech. 142 (2003), 692-696.

DOI: https://doi.org/10.1016/s0924-0136(03)00806-9

[7] J. -Q. Su, T.W. Nelson, R. Mishra, M. Mahoney, Microstructural investigation of fiction stir welded 7050-T651 aluminium, Acta Mater. 51 (2003), 713-729.

DOI: https://doi.org/10.1016/s1359-6454(02)00449-4

[8] P. Carlone, G.S. Palazzo, Experimental analysis of the influence of the process parameters on residual stress in AA2024-T3 friction stir welds, Key Eng. Mat., 504-506 (2012), 753-758.

DOI: https://doi.org/10.4028/www.scientific.net/kem.504-506.753

[9] P.M.G.P. Moreira, A.M.P. de Jesus, A.S. Ribeiro, P.M.S.T. de Castro, Fatigue crack growth in friction stir welds of 6082-T6 and 6061-T6 aluminium alloys: A comparison, Theor. Appl. Fract. Mec. 50 (2008), 81-91.

DOI: https://doi.org/10.1016/j.tafmec.2008.07.007

[10] P.M.G.P. Moreira, F.M.F. de Oliveira, P.M.S.T. de Castro, Fatigue behavior of notched specimens of friction stir welded aluminium alloy 6063-T6, J. Mater. Process. Tech. 207 (2008), 283-292.

DOI: https://doi.org/10.1016/j.jmatprotec.2007.12.113

[11] S. Kainuma, H. Katsuki, I. Iwai, M. Kumagai, Evaluation of fatigue strength of friction stir butt-welded aluminum alloy joints inclined to applied cyclic stress, Int. J. Fatigue 30 (2008), 870-876.

DOI: https://doi.org/10.1016/j.ijfatigue.2007.06.007

[12] O. Hatamleh, A comprehensive investigation on the effects of laser and shot peening on fatigue crack growth in friction stir welded AA 2195 joints, Int. J. Fatigue 31 (2009), 974-988.

DOI: https://doi.org/10.1016/j.ijfatigue.2008.03.029

[13] R.K. Uyyuru, S.V. Kailas, Numerical Analysis of Friction Stir Welding Process, J. Mater. Eng. Perform 15 (2006), 505-518.

DOI: https://doi.org/10.1361/105994906x136070

[14] H Schmidt, J Hattel, A local model for the thermomechanical conditions in friction stir welding, Model. Simul. Mater. Sc. 13 (2005), 77–93.

[15] M. Peel, A. Stewer, M. Preuss, P.J. Withers, Microstructure, mechanical properties and residual stress as a function of welding speed in aluminium AA5083 friction stir welds, Acta Mater. 51 (2003), 4791-4801.

DOI: https://doi.org/10.1016/s1359-6454(03)00319-7

[16] H. Lombard, D.G. Hattingh, A. Steuwer, M.N. James, Effect of process parameters on the residual stresses in AA5083-H321 friction stir welds, Mat. Sci. and Eng. A-Struct. 501 (2009), 119–124.

DOI: https://doi.org/10.1016/j.msea.2008.09.078

[17] K. Deplus, A. Simar, W. Van Haver, B. de Meester, Residual stresses in aluminium alloy friction stir welds, Int. J. Adv. Manuf. Tech. 56 (2011), 493–504.

DOI: https://doi.org/10.1007/s00170-011-3210-0

[18] M.T. Milan, W.W. Bose Filho, J.R. Tarpani, A.M.S. Malafaia, C.P.O. Silva, B.C. Pellizer, L.E. Pereira, Residual Stress Evaluation of AA2024-T3 Friction Stir Welded Joints, J. Mater. Eng. Perform 16 (2007), 86-92.

DOI: https://doi.org/10.1007/s11665-006-9013-z

[19] P. Carlone, R. Citarella, M. Lepore and G.S. Palazzo, Numerical Crack Growth Analysis in AA2024-T3 Friction Stir Welded Butt Joints, Proceedings of The Eighth International Conference on Engineering Computational Technology, 4-7 September 2012, Dubrovnik–Croatia. ISSN: 1759-3433. DOI: 10. 4203/ccp. 100.

DOI: https://doi.org/10.4203/ccp.100.91

[20] M.B. Prime, Cross-sectional mapping of residual stresses by measuring the surface contour after a cut, J. Eng. Mater. -T ASME 123 (2001), 162-168.

DOI: https://doi.org/10.1115/1.1345526

[21] R. Citarella, G. Cricrì, M. Lepore, M. Perrella, DBEM and FEM Analysis of an Extrusion Press Fatigue Failure. In: A. Öchsner, L.F.M. da Silva, H. Altenbach (eds. ), Materials with Complex Behaviour – Advanced Structured Materials, 2010, Volume 3, Part 2, 181-191, DOI: 10. 1007/978-3-642-12667-3_12. Springer-Verlag, Berlin, Germany, 2010. ISBN: 978-3-642-12666-6.

DOI: https://doi.org/10.1007/978-3-642-12667-3_12

[22] M.K. Sadananda, A.K. Vasudevan, Short crack growth and internal stresses, Int. J. Fatigue 19 (1997), 99-108.

DOI: https://doi.org/10.1016/s0142-1123(97)00057-1

[23] R. Citarella, G. Cricrì, A two-parameter model for crack growth simulation by combined FEM-DBEM approach, Adv Eng. Softw. 40 (2009), 363-373.

DOI: https://doi.org/10.1016/j.advengsoft.2008.05.001

[24] P. Carlone, G.S. Palazzo, Influence of Process Parameters on Microstructure and Mechanical Properties in AA2024-T3 Friction Stir Welding, submitted to J. Mater. Eng. Perform (2012).

DOI: https://doi.org/10.1007/s13632-013-0078-4

Fetching data from Crossref.
This may take some time to load.