PSI - Issue 82

L. Mata et al. / Procedia Structural Integrity 82 (2026) 16–23 Mata et al./ Structural Integrity Procedia 00 (2026) 000–000

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X

Y

Fig. 1. Specimen geometry used in the numerical simulations and experimental tests (dimensions in millimetres).

(a)

(b)

Fig. 2. Three-dimensional finite element model developed in the present study: (a) tension-torsion fatigue loading; (b) notch region.

2. Material and methods The material utilised in this study is AlSi10Mg aluminium alloy produced by selective laser melting. The specimens were manufactured using a Renishaw AM400 3D printer, with a scanning speed of 1.8 m/s, and a maximum laser power of 350 W, by vertically stacking 30 μm thickness layers. Its nominal chemical composition is summarised in Table 1. Two material conditions were analysed: untreated (as-built and polished) named UT, and stress-relieved (heat treated and polished) named SR. The heat treatment for the residual stress relief was performed at a temperature of 250º C for two hours, followed by water quenching.

Table 1. Chemical composition of AlSi10Mg aluminium alloy in weight percentage (Fernandes, 2021).

Al

Si

Mg

Mn

Cu

Ni

Fe

Zn

Pb

Sn

Ti

Rem.

9-11

0.25-0.45

0.45

0.05

0.05

0.55

0.10

0.05

0.05

0.15

The numerical simulations were carried out using the specimen geometry presented in Fig. 1. Two tridimensional finite element (FE) models were created to simulate the stress-strain response near the hole region: one for the bending torsion loading scenario, and another for the tension-torsion loading scenario. In both cases, a parametric mesh composed of 20-node hexahedral isoparametric elements was created, using a homogenous, linear-elastic and isotropic material model. In the region surrounding the notch, a finely refined mesh was implemented, to better obtain the stress strain field distribution in the area of interest. The mesh was coarser in the regions farther from the hole to reduce computation time. The bending-torsion loading model, developed using the strategy proposed by Branco et al. (2021), was composed of 700,672 elements and 738,158 nodes. The tension-torsion loading model, see Fig. 2, consisted of 718,624 elements and 757,598 nodes. In the region surrounding the notch, a 70,720-element ring-type mesh was defined for both models. One end of the specimen (top) was fixed, while the other (bottom) was used to apply the cyclic loadings.