PSI - Issue 58

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Aleksandar Grbovic et al. / Procedia Structural Integrity 58 (2024) 42–47 A. Grbovic et al. / Structural Integrity Procedia 00 (2019) 000–000

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The research presented here was a part of broader investigation, based on three main steps, Solob, (2021), Solob et al, (2020), Grbović et al, (2023), Grbović et al, (2023): i) analytical evaluation of loads acting on the wing of the light aerobatic aircraft during the flight, ii) experimental analysis of real aerobatic aircraft wing under presumed loads, and iii) numerical simulation using the extended finite element method (XFEM). Here, focus is on the second step, which was conducted primarily to verify numerical simulation (step iii). 2. Experimental research As shown recently, Solob, (2021), Solob et al, (2020), Grbović et al, (2023), Grbović et al, (2023), numerical simulations of wing behavior enable reliable prediction of its reactions to specific loading conditions. Numerical modelling is not expensive, compared to prototype manufacturing and full-scale wing testing, but its accuracy has to be verified by experimental research under the same load and all other condition. Toward this aim, a single set of wings (Fig. 1) has been manufactured to validate the mechanical behavior under different loading conditions and to verify numerical results. As one can see in Fig.1, the wing prototype has a completely functional aileron and flap, while Fig. 2 shows the shape of rib number 11. All elements of the wing prototype have been manufactured using aluminium alloy 2024-T3, except the wing-fuselage attachment, which was made of a high-strength steel.

Fig. 2. Rib No. 11.

Fig. 1. Wing prototype.

Bending load of wings is supported by the spar, connected to the fuselage through wing-fuselage attachment, comprising two components: one is part of the spar, the other of the main fuselage frame (bulkhead). They both have two pairs of lugs, connected by pins. To reduce experimental costs, a simple thick steel plate with holes (Fig. 2) was used instead, Solob, (2021). The steel plate has two pairs of lugs that fit the lugs of the spar, while the holes on the other side are used to attach the wing to steel I-beams in the laboratory (test bench, Fig. 3), thus holding the wing in a horizontal position during tests, Fig. 4.

Fig. 4. Wing in a horizontal position during tests.

Fig. 3. Test bench.