PSI - Issue 52

Quaiyum M. Ansari et al. / Procedia Structural Integrity 52 (2024) 122–132 4 Quaiyum M. Ansari/ Fernando Sánchez/Luis Doménech-Ballester/ Trevor M. Young/ Structural Integrity Procedia 00 (2019) 000 – 000

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Keegan [33] performed the impact of hailstones and raindrops on LEP to better understand the induced damage and erosion mechanism. The modelling methodologies developed in this work are useful in developing a cutting-edge design by gaining a fundamental understanding of the impact response of leading edge turbine blade protection systems. Marzbali et al. [34] published a review on the mechanisms of liquid impingement erosion and liquid solid impact. This recently published review paper summarised current knowledge about liquid droplet erosion and discussed the various mechanisms that influence erosion. Therefore, the objective of the current work is to develop a robust FE model that can correlate well with tested coupon failure modes in order to evaluate coatings and develop more robust coating designs. 2. Methodology In this work, low velocity impact has been investigated using an axisymmetric model, to understand the impact phenomena and to extract the forces in an explicit FE model. To accomplish this, a rigid plate and droplet assembly have been created as shown in Fig. (3). The FE model is then validated using experimental results from the literature [28]. The high velocity impact is then simulated using an axisymmetric model. Next, a 3D FE model for rain droplet impact on the solid plate is then created. Finally, a 3D LEP coating system model with various layers such as LEP coating, primer, filler, and substrate has been developed in order to comprehend the failure mechanism and evaluate the LEP coating for an offshore wind turbine.

Fig. 3. Axisymmetric model (a) front view (b) 3D sectional view The impact force is generated when the droplet collides with a solid surface. The theoretical average impact force can be calculated as follows [28]: = 2 (1) where is mass, is the velocity and is the diameter of the droplet. Furthermore, Eqn. (1) can be rewritten as, = ∆ = ℎ (2) where, ℎ are impulse and is the time duration of droplet impact. This can also be calculated as the area under the force-time curve. The peak force and impulse can be written, respectively, as [32], =0.84 2 2 (3)