采用碳纤维增强复合材料贮箱可显著减轻运载火箭的质量，但贮箱在低温环境中机械-热载荷作用下的分析方法有待研究，尤其是要准确地考量纤维与基体间产生的细观热应力。采用包含多根纤维的代表体元模型，结合基体、纤维失效准则，建立了细观应力场及失效预测模型，并采用k-means聚类方法开展降维计算，提出了一种高效、高精度复合材料贮箱跨尺度分析方法。结果显示：该方法能够根据纤维和基体的热、力学常数准确地预测复合材料单层板的弹性常数和破坏强度；结合某贮箱模型，模拟了机械-热载荷共同作用下复合材料贮箱渗漏失效的发生过程，给出了明确的失效载荷及失效状态。

Using the carbon fiber-reinforced composite tank can remarkably reduce the weight of the launch vehicle.However，the analysis method for cryogenic tanks subjected to mechanical-thermal loads remains to be studied，especially to accurately consider the microthermal stress produced between fiber and matrix in the cryogenic environment.A representative volume model containing multiple fibers was adopted，combined with the matrix and fiber failure criteria，to establish a microscopic stress field and failure prediction model.The k-means clustering method was used for dimensionality reduction calculation，and an efficient and high-fidelity trans-scale analysis method for composite tanks was proposed.The results of illustrative examples show that the proposed method can accurately predict the elastic constants and failure strength of the composite single-layer plate according to the thermal and mechanical constants of fiber and matrix.The leakage failure process of a composite tank subjected to mechanical-thermal loads was simulated，and the critical load and failure state were given.