Strength of filament wound thick-walled cylindrical vessel under internal and external pressure
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摘要: 研究各向同性材料内胆外对称均衡缠绕纤维的厚壁圆柱形容器在内外压力作用下的应力和强度特性。采用正交各向异性本构关系和轴对称厚壁筒理论, 获得纤维层和内胆的应力, 以及纤维方向三向应力的解析公式。利用Hoffman和Tsai-Wu失效准则研究薄壁筒理论和三维应力对应的强度随壁厚和缠绕角的分布规律。计算比较了有、 无内胆的纤维缠绕容器的强度随缠绕角的变化情况。利用ANSYS软件的层合单元SOLID191建立的模型给出的纤维向应力和强度比与本文理论结果吻合很好。研究发现: 基于层合板理论的二维纤维向应力公式给出了不准确的纤维向应力, 不准确的横向应力造成容器纤维层的强度值偏低; 不同的纤维类型和缠绕角, 厚度-半径比对强度比的影响不同; 基于二维应力分析的薄壁筒理论给出的纤维层强度比小于三维分析的结果; 缠绕角对无内胆的缠绕容器强度比的影响比有内胆的更敏感。Abstract: The strength of a thick-walled vessel with alternate-ply filament winding(FW) outside an isotropic liner under internal and external pressure was investigated by three-dimensional (3D) orthotropic stress-strain relation and axisymmetric thick-walled cylinder theory. The stresses of the liner and the fiber layer, as well as longitudinal stress along the fiber direction, transverse stresses perpendicular to the fiber direction and shear stress were obtained analytically. Using Hoffman failure criteria and Tsai-Wu 3D failure criteria, the strength of the filament layer of FW cylinder with respect to thickness and winding angle was investigated by the thin-walled theory and 3D theory, respectively. The strength of FW vessel with a liner with respect to winding angle was compared numerically with FW vessel without a liner. Numeric results of finite element (FE) model were presented in ANSYS software by layered element SOLID191, and perfect agreement of stresses in fiber directions and strength ratio between FEA and the theory was achieved. It is found that the laminate theory gives imprecise two dimensional fiber stresses, in which transverse stresses lead to lower strength estimation. The influence of the thickness-radius ratio to strength ratio is different for different filament types and winding angles, and the strength ratio given by 3D stress analysis under external pressure is far beyond the thin-walled theory. The comparison shows that the strength ratio of FW vessel without a liner is more sensitive to winding angle than the vessel with a liner.
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Key words:
- filament winding /
- thick-walled vessel /
- FEA /
- failure criteria /
- fiber stress /
- strength ratio
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