LAUSR

With the continuous development of the energy and power industry, Glass Fiber Reinforced Polymer (GFRP) is increasingly used in high‐voltage insulation applications. However, in practical operations, the multi‐field coupling effects, such as wet‐heat‐electricity, can reduce various properties of GFRP materials. The resulting moisture absorption deterioration problem has become an important factor affecting the safe and stable operation of electrical equipment. This study investigates the performance degradation behavior of GFRP, revealing the aging mechanisms under the coupled effects of wet‐heat‐electricity, and clarifying the impact of different aging stages on the material's comprehensive performance. Microscopic characterization methods were used to analyze changes in the surface morphology and elemental composition of GFRP under coupled effects, while electrical testing was used to study changes in its charge characteristics and insulation strength. The correlation between the microscopic characteristics and macroscopic properties of the performance deterioration of GFRP composites with different aging stages was established. The results show that the moisture absorption characteristics of the material basically conform to the two‐stage model, namely the early Fick diffusion stage and the later performance degradation stage. Based on the molecular dynamics simulation analysis, it is believed that the invasion of water will disrupt the cross‐linked system of epoxy, increase the free volume, and thereby further accelerate the invasion and destruction of water.