PSI - Issue 52

Quaiyum M. Ansari et al. / Procedia Structural Integrity 52 (2024) 122–132 Quaiyum M. Ansari/ Fernando Sánchez/Luis Doménech-Ballester/ Trevor M. Young / Structural Integrity Procedia 00 (2019) 000 – 000 7

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and reaches zero when the time is near 40 µs to 50 µs. Furthermore, the total impact duration decreases while the peak impact force increases. Finally, the peak force calculated from Eq. (3) correlates well with the peak force calculated numerically. The theoretical peak force for 160 m/sec, for example, is 181 N, while the FE peak force is 180 N.

Fig. 7. FE force time plot for different velocities for 2.9 mm droplet.

3.2. 3D modelling Figure (8) shows the 3D FE modelling for the 2.0 mm droplet impact on the 1.0 mm thick Aluminium (AL) substrate. A 27 mm diameter disc is considered for the substrate, keeping in mind that the size of coupons is typically tested at the University of Limerick's WARER rain erosion rig. The ball is made up of linear tetrahedral elements (C3D4), while the substrate is made up of linear hexahedral elements (C3D8R). On the substrate, a finer mesh is created at the center near the impact and the remaining area is meshed with a coarser mesh. Following the mesh convergence study, 209203 elements have been created on the droplet and 194300 elements have been created on the plate. The droplet velocity is applied in the downward direction and the substrate is fixed at the edges.

Fig. 8. FE model for 2.0 mm droplet impact on Aluminium substrate. Table 1 depicts a 2.0 mm droplet impacting at 100 m/sec, with the droplet undergoing 50% deformation in 6 µs. When a droplet strikes a surface, its velocity decreases over time and the droplet deforms radially outward, as observed in experiments. Furthermore, Fig. (9) depicts the peak force during impact at various velocities, and it is found that the peak force correlates well with the theoretically calculated peak force from Eq. (3). With theoretically calculated