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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Table 1. (a) The material properties of the 3D printed aerofoil section based on the Vero Family (Stratasys, 2018) and (b) the mesh properties simulated using Solidworks.

(a) Material Properties

Value (Units) 2000E+06 N/m 2

(b) Mesh Properties

Information

Elastic Modulus Poisson’s Ratio Yield Strength Mass Density Tensile Strength

Mesher Used

Blended curvature-based mesh

0.394

Jacobian Points for Mesh

16 points

75E+06 N/m 2 1175 kg/m 3 50E+06 N/m 2

Total Nodes

101185 58784 17.095

Total Elements

Maximum Aspect Ratio

2.3. Aerodynamic Database The pressure distribution around the aerofoil is an important aerodynamic parameter that, together with the structural properties of the aerofoil, will determine the structural response. The DT platform presented in this paper uses XFOIL to generate the pressure distributions which form the aerodynamic database. The main advantage of using XFOIL in this work is that it produces low-fidelity results that significantly reduce the computational costs compared to performing higher-order CFD computations. XFOIL calculates the C p using the Karman-Tsien compressibility correction which allows for good compressible predictions all the way to sonic conditions (Drela, 2013). The database was generated for EV’s Cobra aircraft which has a ceiling height of h = 5 km and a maximum speed of M ∞ = 0.30 during the cruise flight phase. The database is valid for α ∞ values where the flow is attached as XFOIL solutions do not converge when the flow is separated. From the C p generated using XFOIL, the static pressure, p , can be calculated using equation (1), = ( 1 2 ∞ ∞ )+ ∞ (1) where ρ ∞ is the air density, U ∞ is the freestream velocity and p ∞ is the freestream pressure. The lift, L , and drag, D , can be calculated from the lift and drag coefficients, C L and C D using equations (2) and (3). = ( 1 2 ∞ ∞ ) × × (2) = ( 1 2 ∞ ∞ ) × × (3) where c is the aerofoil chord and w is the aerofoil width. These dimensions are sketched in Figure 2. 3. Results and Discussion 3.1. Aerodynamic Behaviour Using XFOIL, the pressure distribution around the aerofoil was calculated for 5 different velocities, U ∞ and α ∞ = 0 o , with the results shown in Figure 3. These pressure distributions are part of the aerodynamic database. For these conditions, the lift and drag values are calculated from their respective coefficients using equations (2) and (3) with the results shown in Table 2. As M ∞ increases, both the lift and drag values increase as well. Experimentally, for the same conditions, the Gamma IP65 load cell (ATI Novanta, 2025) was used to measure the total forces in the x , y and z directions; corresponding to the lift, drag and spanwise forces respectively. The results are shown in Table 3. The aerofoil section is short and stiff, therefore the aerodynamic loading in the spanwise direction can be considered as constant under steady-state conditions. Comparing the numerical predictions of XFOIL in Table 2, the experimental