极地船舶冰载荷分布尾部（高载荷区域）特性的精准建模对结构安全具有决定性影响，现有分布模型对尾部数据拟合精度不足，船舶抗冰设计可靠性受限。为突破标准分布模型的局限性，本文提出高精度尾部拟合方法，为极地船舶可靠性设计提供理论支撑。基于实测冰载荷，采用瑞利分离器提取峰值数据，提出非线性混合指数分布模型，提升尾部拟合适应性。结合分位数-分位数图与尾部决定系数，综合对比指数分布、威布尔分布、指数威布尔分布、线性混合指数分布及非线性混合指数分布的拟合效果。结果表明，本文所提出的分布模型尾部决定系数在所有冰载荷峰值数据集上均大于0.85，在所有对比分布中拟合效果最优，能够精准表征冰载荷尾部特征，为船舶抗冰结构设计与风险评估提供可靠依据。

Accurate modelling of the characteristics of the distribution tail (high ice force area) of the ice force of polar ships has a decisive impact on structural safety, and the existing distribution model has insufficient accuracy in fitting the tail data, which limits the reliability of the safety design of ships. In order to overcome the limitations of the standard distribution model, this paper proposes a high-precision tail fitting method to provide theoretical support for the reliability design of polar ships. In this paper, based on the measured ice force, the Rayleigh separator is used to extract the peak data, and a nonlinear mixed index distribution model is proposed to improve the fitting adaptability of the tail. Combined with the quantile-quantile plot and the coefficient of determination, the goodness of fitting of exponential distribution, Weibull distribution, exponential Weibull distribution, linear mixed exponential distribution and nonlinear mixed exponential distribution were comprehensively compared. The results show that the tail coefficient of determination of the distribution model proposed in this paper is greater than 0.85 on all ice force datasets, and the goodness of fitting is the best among all the compared distributions, which can accurately characterize the tail characteristics of ice force and provide a reliable basis for the design and risk assessment of ship ice-resistant structures.