PSI - Issue 80

Tafara E. Makuni et al. / Procedia Structural Integrity 80 (2026) 105–116 Tafara Makuni / Structural Integrity Procedia 00 (2019) 000 – 000

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3.4. Structural Response Given M ∞ , α ∞ and h as inputs, the reconstructed pressure distribution is shown in Figure 9 (a). The average pressure acting on the upper and lower surface is 101,318 Pa and 101,323 Pa respectively and this is used as input to predict the structural response in terms of stress, strain and displacement; σ, ε and δ , respectively. This required the material properties of the 3D printed material to be estimated. The predicted strain and stress fields are shown in Figure 9 (b) and (c), with the tabulated maximum and minimum values given in Table 4. The strain and reconstructed pressure are to be verified by SG and PT readings from the aerofoil upper surface. On the upper surface, the model is instrumented with 10 PTs of which, 4 lie on the centreline and the remaining 6 are off-centre. On the lower surface there are 2 PTs both of which the centreline. There are 5 uniaxial SGs on the upper surface, and 2 uniaxial SGs on the lower surface.

(b)

(a)

(c)

Figure 9: (a) Reconstructed pressure distribution acting across the aerofoil for U ∞ = 5 ms -1 and α ∞ = 0 o , (b) the corresponding strain field and (c) the corresponding stress field.

Table 4: The minimum and maximum stress, strain and displacement values for U ∞ = 5 ms -1 and α ∞ = 0 o . Minimum Value Maximum Value Stress, σ 11,490 N/m 2 51,850,000 N/m 2 Strain, ε 3.468 µm 19.10 mm Displacement, δ 0 mm 2.895 mm

4. Conclusions In this paper, a methodology for developing a DT platform for aerodynamic load reconstruction and structural response estimation is presented and has been preliminarily tested using a simple experimental setup. The reconstructed aerodynamic loading was used as an input to calculate the structural response of a NACA3418 aerofoil section. The reconstructed load and strain field require verification through further experiments, which is planned to be carried out next. The laboratory model of the aerofoil section was 3D printed at ICL, tested experimentally in the T1 wind tunnel and the force measurements obtained from a 6-component load cell showed good agreement to the force values low-fidelity simulations conducted using XFOIL. The main inputs to the DT model are; M ∞ , α ∞ and h ; however, since in real applications, it is not possible to have pressure distribution over the whole aerofol measured, the input to the surrogate model is pressure values at several points, to represent in service sensor output. The surrogate model is constructed based on BRBP ML which then outputs the pressure field over the wing section. Aerodynamically, the main output of the DT model is the pressure field, and structurally, the main output is the strain field. A BRBP ML model was found to be accurate in reconstructing the aerodynamic loading given M ∞ , α ∞ , h . and the pressure values at 4 different points as inputs. Experimentally, the flow field around the aerofoil section was visualised using flow tufts where the flow was found to be separated towards the trailing edge of the model and on the tunnel flow. Further experimental and computational modelling is being carried out to develop this DT, with the laboratory model being extended to a wing span.