基于弹性基础梁理论的复合材料薄壁圆柱壳屈曲承载力模型

提出一种复合材料薄壁圆柱壳轴压局部屈曲承载力计算模型。在梁弯曲变形平截面假定和小变形假定的基础上,提出复合材料层合梁抗弯刚度的计算方法;根据轴压下圆柱壳的几何对称性及受力对称性,将圆柱壳局部屈曲问题转化为轴向和环向壳带的弯曲变形问题。依据薄壳稳定理论,建立弹性基础上纵向壳带局部屈曲模型,得到了复合材料圆柱壳屈曲承载力解析公式。理论计算公式与经验工程计算公式相比,具有形式上的相似性,且得到的计算系数可直接求出,而非经验范围选取。对三种铺层的复合材料薄壁圆柱壳进行了轴压试验,结合文献试验数据对比,试验结果与理论预测值基本一致,满足工程精度要求,验证了模型的正确性。

A model for critical buckling load of thin composite tube based on elastic foundation beam theory

A computation model for critical buckling load of composite thin tube was presented.Based on the plane hypothesis and small deformation assumption,a simplified method was presented for equivalent bending stiffness of composite beam.According to the geometrical symmetry and force symmetry of tube under axial compression,the local buckling of tube was transformed into the problem of the bending deformation of the axial and circumferential strips.On the basis of the stability theory of shell,the computation model for the stability of longitudinal strip on elastic foundation was established,and the analytical formula for the buckling bearing capacity of the composite tube was obtained.Compared with the engineering calculation formula,they are similar in form and the correction factor can be obtained directly from the model,rather than from experience.Axial compression test of three kinds of laminated composite tubes was conducted,and the experimental results are consistent with the theoretical prediction.Comparing the experimental data in literature with the theoretical calculation results,the deviation meets the requirements of engineering accuracy,which verifies the correctness of the model.