For simplifying the analysis of stiffening cylindrical shell in rocket, the computational method of torsional rigidity in the area-equivalence method was studied for the stringers in stiffening cylindrical shell, it is shown that the effect of stringers on the torsional rigidity of stiffening cylindrical shell is negligible. The equivalent beam or shell model with uniform thickness, the equivalent shell model with varied thickness and three dimensional （3-D） beam-shell model were proposed to solve the inherent torsional vibration frequency, and the features of these models were discussed. It was theoretically revealed that the obtained equivalent thickness by the area-equivalence method could not be directly used to calculate the torsional rigidity. Two modification methods, namely, the rigidity reduction method and frequency modified method, were presented when the equivalent thickness was directly utilized to solve the torsional frequencies. Numerical comparisons validate the proposed methods and models.%为了给火箭等加筋圆柱壳结构的简化计算提供理论基础，研究了加筋圆柱壳面积等效方法中的扭转刚度计算方法，说明了不能直接根据等效厚度计算扭转刚度的物理机理，得到了桁条对圆柱壳扭转刚度的贡献可以忽略的结论．根据等效厚度以及桁条与蒙皮连接关系的不同处理方法，给出了计算扭转固有振动频率的等效梁模型、变厚度壳模型和壳一梁模型，分析了桁条在3种模型中对刚度和质量（包括转动惯量）的不同作用．为了消除根据等效厚度计算扭转刚度和扭转固有振动频率的偏差，分别给出了扭转刚度和扭转固有振动频率的修正方法．数值结果验证了修正方法和所得结论的正确性．
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