大型CFRP薄壁管桁架加劲环稳定性研究

Stability performance of stiffening rings on large CFRP thin-walled tube trusses

为了深入研究某半硬式平流层飞艇的关键结构部件CFRP薄壁管桁架加劲环的稳定性能,首先对初始构型和不同张拉位移下的构型进行特征值屈曲分析,然后考虑初始预应力和初始几何缺陷,对预张拉工况进行全过程非线性稳定分析,并利用温度荷载对不同张拉位移下的构型进行稳定分析,最后通过大量计算进行初始几何缺陷分析。研究表明:结构首先发生局部屈曲;结构对于初始几何缺陷十分敏感,考虑整体1阶模态的初始缺陷后结构的临界屈曲荷载减小42.91%;结构临界屈曲荷载因子随初始预应力和张拉位移的增大呈线性减小,张拉位移增大时上下径向拉索最大应力之比与其高度之比呈现同样的变化趋势;结构屈曲时径向拉索内力的分布与几何缺陷形式紧密相关,多模态组合缺陷更能反应结构真实几何缺陷。本文对CFRP薄壁管加劲环及同类轮辐式张拉结构的设计、装配、集成等具有重要的参考价值。

To further study the stability performance of the CFRP thin-walled tube truss stiffening ring,the key structural component of a semi-rigid stratospheric airship,the eigenvalue buckling analysis of the initial configuration and the configuration with different tension displacements is carried out.Then,considering the initial prestress and initial geometric imperfections,we examine the nonlinear stability of the whole process of the pre-tensioning condition and the stability of the configuration with different tension displacements using the temperature load.Finally,the initial geometric imperfections are analyzed through calculation.The research shows that the local buckling occurs first;the structure is sensitive to the initial geometric imperfections,and the critical buckling load of the structure is reduced by 42.91% after considering the initial geometric imperfections.The critical buckling load factor of the structure decreases linearly with the increase of initial prestress and tension displacement,and the ratio of the maximum stress of the upper and lower radial cables to their heights exhibits the same trend.The internal force distribution of radial cables is closely related to the form of geometric imperfections during structural buckling,and the multi-model combined imperfections can better reflect the real geometric imperfections of the structure.This paper has important reference value for the design,assembly and integration of CFRP thin-walled tube stiffening rings and similar spoke tension structures.