A Strain-Data-Driven Factor-Wise Inverse Identification Approach for Blown-Sand Erosion Parameters of GFRP Strips

Glass fiber-reinforced polymer (GFRP) is widely used in wind power, construction, and aerospace for its superior properties. However, studies on its blown-sand erosion degradation and prediction remain limited. This study investigates the degradation and prediction of blown-sand erosion behavior in GFRP strips using a one-factor-at-a-time (OFAT) experimental design. Simulated experiments quantify the effects of factors such as erosion angle, velocity, sand flow rate, and erosion time on mechanical behavior. Results show that epoxy-layer deformation and internal fiber fracture increase with erosion angle and velocity. The tensile strength decreased by approximately 16.8% at an erosion angle of 90° when the velocity, sand flow rate, and erosion time were fixed at 26 m/s, 55 g/min, and 30 min, respectively. At an erosion velocity of 31 m/s, with the erosion angle, sand flow rate, and erosion time fixed at 90°, 55 g/min, and 30 min, respectively, the strength reduction reached 28%. Under a 45 g/min sand flow rate, the strength reduction reached 6%, while extending the erosion time to 50 min led to a decrease of 35%. Furthermore, a particle swarm optimization (PSO)-assisted, interpolation-based inverse identification model was established to back-calculate erosion parameters from measured strain fields. The mean in-sample reconstruction error was approximately 4.2%, whereas leave-one-condition-out validation yielded an overall mean error of 31.8%, with factor-specific errors ranging from 12.8% to 43.8%, indicating limited generalization to unseen conditions. This work elucidates the progression of material degradation from initial damage to severe failure and provides laboratory reference data for understanding the post-erosion residual behavior under the investigated erosion-only conditions.