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. 2021 Mar 2;14(5):1176.
doi: 10.3390/ma14051176.

Ultimate Load-Carrying Ability of Rib-Stiffened 2024-T3 and 7075-T6 Aluminium Alloy Panels under Axial Compression

Ján Slota  1 , Andrzej Kubit  2 , Tomasz Trzepieciński  3 , Bogdan Krasowski  4 , Ján Varga  1
Affiliations

Ultimate Load-Carrying Ability of Rib-Stiffened 2024-T3 and 7075-T6 Aluminium Alloy Panels under Axial Compression

Ján Slota et al. Materials (Basel). .

Abstract

Stringer-stiffened panels made of aluminium alloys are often used as structural elements in the aircraft industry. The load-carrying capacity of this type of structure cannot relieve the reduction in strength in the event of local buckling. In this paper, a method of fabrication of rib-stiffened panels made of EN AW-2024-T3 Alclad and EN AW-7075-T6 Alclad has been proposed using single point incremental forming. Panels made of sheets of different thickness and with different values of forming parameters were tested under the axial compression test. A digital image correlation (DIC)-based system was used to find the distribution of strain in the panels. The results of the axial compression tests revealed that the panels had two distinct buckling modes: (i) The panels buckled halfway up the panel height towards the rib, without any appreciable loss of rib stability, and (ii) the rib first lost stability at half its height with associated breakage, and then the panel was deflected in the opposite direction to the position of the rib. Different buckling modes can be associated with the character of transverse and longitudinal springback of panels resulting from local interaction of the rotating tool on the surface of the formed ribs.

Keywords: aluminium alloy; axial compression test; incremental sheet forming; load-carrying capacity; rib-stiffened panel.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Dimensions (in mm) of a rib-stiffened panel fabricated using Single Point Incremental Forming (SPIF).
Figure 2
Figure 2
Device for incremental forming mounted in the table of a numerically controlled TM-1P vertical milling machine.
Figure 3
Figure 3
Tool strategy.
Figure 4
Figure 4
Fracture in the corner of the rib formed in 0.4-mm-thick EN AW-2024-T3 sheet.
Figure 5
Figure 5
Rib-stiffened panel mounted in the grips of the tensile testing machine.
Figure 6
Figure 6
The view of the panel with grid of points.
Figure 7
Figure 7
Modes of panel buckling: (a) Mode A—the panels buckled halfway up the panel width towards the rib, without any appreciable loss of rib stability and (b) Mode B—the rib first lost stability at half height, which was associated with breakage of the rib, and then the panel was deflected in the opposite direction to the position of the rib
Figure 8
Figure 8
Effect of vertical pitch on the manner of interaction of the tool with the sheet metal at (a) small and (b) high value of vertical pitch.
Figure 9
Figure 9
Load-displacement curves of the panels fabricated from 0.4-mm-thick EN AW-2024-T3 Alclad panels subjected to compression load.
Figure 10
Figure 10
Buckling mode of 0.4-mm-thick EN AW-2024-T3 Alclad panel: (a) Mode A—the panels buckled halfway up the panel width towards the rib, without any appreciable loss of rib stability; (b) Model B—the rib first lost stability at half height, which was associated with breakage of the rib, and then the panel was deflected in the opposite direction to the position of the rib.
Figure 11
Figure 11
Load-displacement curves of the panels fabricated from 0.8-mm-thick EN AW-7075-T6 Alclad panels subjected to compression load.
Figure 12
Figure 12
Buckling mode of 0.8-mm-thick EN AW-7075-T6 Alclad panel: (a) Mode A—the panels buckled halfway up the panel width towards the rib, without any appreciable loss of rib stability; (b) Mode B—the rib first lost stability at half height, which was associated with breakage of the rib, and then the panel was deflected in the opposite direction to the position of the rib.
Figure 13
Figure 13
Load-displacement curves of the panels fabricated from 1-mm-thick EN AW-2024-T3 panels subjected to compression load.
Figure 14
Figure 14
Buckling mode of 1-mm-thick EN AW-2024-T3 panel: (a) Mode A—the panels buckled halfway up the panel width towards the rib, without any appreciable loss of rib stability; (b) Mode B—the rib first lost stability at half height, which was associated with breakage of the rib, and then the panel was deflected in the opposite direction to the position of the rib.
Figure 15
Figure 15
Forming limit diagram for a panel made of 1-mm-thick EN AW-2024-T3 sheet.
Figure 16
Figure 16
Distributions of (a) thickness and of (b) thinning of the rib fabricated in 1-mm-thick EN AW-2024-T3.
Figure 17
Figure 17
SEM micrographs of the fracture surface of a panel made of 0.5-mm-thick EN AW-2024-T3 Alclad sheet: Micrographs (a–d) show various fragments of the ductile fracture.
Figure 18
Figure 18
SEM micrographs of the fracture surface of a panel made of 0.8-mm-thick EN AW-7075-T6 Alclad sheet: Micrographs (a–d) show various fragments of the ductile fracture.
See this image and copyright information in PMC

References

    1. Vijayakumar M., Dhinakaran V., Sathish T., Muthu G., Ram P.B. Experimental study of chemical composition of aluminium alloys. Mater. Today Proc. 2020 doi: 10.1016/j.matpr.2020.07.391. - DOI
    1. Choi Y., Lee J., Panicker S.S., Jin H.-K., Panda S.K., Lee M.-G. Mechanical properties, springback, and formability of W-temper and peak aged 7075 aluminum alloy sheets: Experiments and modeling. Int. J. Mech. Sci. 2020;170:105344. doi: 10.1016/j.ijmecsci.2019.105344. - DOI
    1. Löveborn D., Larsson J., Persson K.-A. Weldability of Aluminium Alloys for Automotive Applications. Phys. Procedia. 2017;89:89–99. doi: 10.1016/j.phpro.2017.08.011. - DOI
    1. Landowski M., Świerczyńska A., Rogalski G., Fydrych D. Autogenous Fiber Laser Welding of 316L Austenitic and 2304 Lean Duplex Stainless Steels. Materials. 2020;13:2930. doi: 10.3390/ma13132930. - DOI - PMC - PubMed
    1. Santos M.C., Machado A.R., Sales W.F., Barozzo M.A.S., Ezugwu M.O. Machining of aluminum alloys: A review. Int. J. Adv. Manuf. Technol. 2016;86:3067–3080. doi: 10.1007/s00170-016-8431-9. - DOI

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