Wind turbine blade is the key component to capture wind power, and it is mainly composed of glass fiber reinforced polymer (GFRP). Due to the randomness and volatility of wind speed in nature, wind turbine blade is usually subjected to the alternate action of normal and extreme wind loads during its long-term service. In this study, a reliability model that considering the stochastic wind loads and strength degradation of GFRP is proposed. Firstly, a residual strength model is developed based on the Palmgren-Miner (P-M) damage theory and the same damage state (SDS) principle, which is capable of characterizing the strength degradation law of GFRP under the normal wind load. Then, the alternate actions of normal and extreme wind loads are considered, and a dynamic reliability model is presented based on Poisson process and mathematical derivation. Finally, the traditional discrete stress-strength interference (DSSI) model is extended to calculate the dynamic reliability when probability distributions of stochastic wind loads and residual strength of GFRP are unknown. The wind load data and GFRP test data are utilized to demonstrate the effectiveness of the proposed model. The result shows that the reliability of GFRP keeps at a high level in the early stage, then it rapidly decreases due to the accumulation of fatigue damage.

风力涡轮机叶片是捕获风能的关键部件，主要由玻璃纤维增​​强聚合物（GFRP）组成。由于自然风速的随机性和波动性，风力涡轮机叶片在其长期使用期间通常经受正常和极端风载荷的交替作用。在这项研究中，提出了一种考虑了随机风荷载和玻璃钢强度退化的可靠性模型。首先，基于Palmgren-Miner（PM）损伤理论和相同损伤状态（SDS）原理建立了残余强度模型，该模型能够表征正常风荷载下GFRP的强度退化规律。然后，考虑了正常和极端风荷载的交替作用，并基于泊松过程和数学推导建立了动态​​可靠性模型。最后，当未知随机风荷载的概率分布和玻璃钢的残余强度时，扩展了传统的离散应力-强度干涉（DSSI）模型来计算动态可靠性。利用风荷载数据和GFRP测试数据来证明所提出模型的有效性。结果表明，GFRP的可靠性在早期保持较高水平，然后由于疲劳损伤的积累而迅速降低。