中文摘要：

将复合材料弹性参数偏轴转换理论引入Hedgepeth细化模型,使模型应用范围拓展到倾斜切缝。进而应用Griffith能量理论,并结合试验现象,针对倾斜切缝模型推导了蒙皮材料抗撕裂强度公式。由理论结果可知,蒙皮材料的抗撕裂强度与材料的内因（弹性参数、纱线编织密度等）及外因（切缝倾角、切缝长度等）有关,是由膜材材料性质及损伤参数共同决定的。通过与其他撕裂强度理论及试验结果进行对比分析,验证了所推导理论及所得结论的正确性。所得结论可为蒙皮材料的强度设计及飞艇结构的安全性评估提供理论参考。

英文摘要：

The off-axis elastic constants theory for composites was applied in the Hedgepeth＇s model to make the model workable for all cracks with inclined orientations.Then,according to the Griffith energy theory and the test phenomena,a theoretical formula was derived to evaluate the tearing strength of envelope materials with central cracks.The results demonstrate that the tearing strengths are affected by the internal factors（such as the elastic constants,weaving density,etc）and external factors（such as the inclined orientation,crack length,etc）.Furthermore,the precision and applicability of the formula were verified with the test result and the other tearing strength theories.Investigations on the tearing strength of envelope materials will provide significant guidance for the strength design and safety assessment of airship structures.