Lifetime Prediction of Microwave Cured Coated GFRP Composite Using Rain Erosion Test for Wind Turbine Blade Applications

Abstract An epoxy-coated glass fiber-reinforced polymer (EcGFRP) composite was manufactured using a vacuum-assisted resin infusion microwave curing (VARIMC) process. The epoxy coating on the composites was cured using microwave irradiation. The cumulative volume loss (CVL) (1316.8 mm3) on the composite was determined from a 540 h experimental whirling arm rain erosion test (RET). The impingement, H, representing the accumulated rain column equivalent to actual precipitation, was calculated from experimental results. The CVL versus H data were fitted to power law and Weibull cumulative distribution function (CDF) analytical models and H was calculated for both. Precipitation data from 18 stations using Integrated Multi-satellitE Retrievals for global precipitation measurement (IMERG) and in situ datasets were utilized to predict the lifetime of the EcGFRP composite. At an incubation time of 156 h, the predicted service life ranged from 4.5 years to 12 years for the in situ method and from 4 years to 10.5 years for the IMERG method. When the CVL reached 0.45 mm3 at 180 h, the estimated service life increased to 5–14 years for the in situ method and 4.6–12 years for the IMERG method. The results indicate the feasibility of the EcGFRP composite in resisting rain erosion damage. Improved lifetime correlates with enhanced mechanical properties under repeated rain impacts, supported by nanoindentation results showing significant short-term recovery ∼60%, indentation modulus ∼4.17 GPa, and higher indentation hardness (∼0.19 GPa).