基于三维梁理论的复合材料层合管等效抗弯刚度

针对任意铺层形式和任意壁厚复合材料圆形层合管件，提出一种等效抗弯刚度的计算方法。此方法采用符合复合材料圆形管件梁真实变形的变形理论，考虑横向剪切变形，非均匀扭转效应，主、次挠曲效应和层合材料的三维弹性效应，按照壳壁中实际应力状态，建立了复合材料圆形管件等效抗弯刚度的计算模型。通过与4种铺层管件的三点弯曲实验结果以及经典层合板理论计算的等效抗弯刚度进行对比，验证了计算模型的正确性。通过退化与各向同性材料抗弯刚度的计算方法进行对比，分析了计算模型的适用性。 

Equivalent bending stiffness of composite laminated tube based on 3D beam theory

In response to composite tube with arbitrary lamination and thickness,an approach of the equivalent bending stiffness was presented.The deformation theory with realistic deformation of composite tube beam was used in this analysis.Transverse shear deformation,non-uniform torsion effects,the primary and the secondary warping effects and 3D elastic effects in laminate material were considered.According to the actual stress state of the shell wall,the caculation model of the equivalent bending stiffness of the composite tube was established.By comparison with three-point bending experimental data and the equivalent bending stiffness calculated by classical laminated plate theory of four composite tubes,the calculation model was validated.The application of the calculation model was analyzed by comparing degradation of the present theory with the calculation method of bending stiffness of isotropic material.