基于变环肋间距的碳纤维/环氧树脂复合材料格栅加筋截顶圆锥壳体稳定性

Stability of advanced grid stiffened carbon fiber/epoxy composite conical shells with novel distribution of circumferential ribs

研究均布外压作用下具有非均匀特征的碳纤维/环氧树脂复合材料格栅加筋(AGS)圆锥壳体构型优化。首先,充分考虑复合材料格栅圆锥壳体中格栅非均匀分布造成结构小端材料利用不充分问题,提出变环肋铺设间距的优化分布方式,使格栅在截顶圆锥壳体结构上小端疏大端密。之后,基于考虑格栅非均匀分布及变环肋间距铺设特征的等效刚度模型,并采用最小势能原理得到环肋铺设优化后的AGS圆锥壳体临界载荷值解析式。针对典型锥壳的有限元验证表明解析算法的误差在1%左右,证实了本文提出的分析方法的可靠性和有效性。最后,通过对环肋间距优化圆锥壳体的参数分析,发现优化环肋分布方式可以使AGS锥壳结构的外压稳定性大幅上升。本文研究内容为碳纤维/环氧树脂复合材料AGS圆锥壳体的优化设计提供了一种具有较高承载力的构型,并为此类结构的计算提供了解析算法。

The influence of rib non-uniform distribution on the stability of advanced grid stiffened（AGS）carbon fiber/epoxy composite conical shells was studied.Firstly,considering the non-uniform distribution of ribs on common AGS conical shells,which ultimately resulted in over safety at the small side,a novel distribution of circumferential ribs was proposed to reduce the spacing between circumferential ribs at the big side,yet to increase the spacing at the small side.Then,the tensile,bending and coupling stiffness matrices of AGS conical shells along the longitudes were deduced based on equivalent stiffness model.With the use of Donnell form of relations for shells and the minimum potential principle,the critical buckling load of typical AGS conical shells was predicted.The relative error of the present analytical model is about only 1%for typical AGS conical shells compared with FEM results,which indicates the accuracy and validity of the analytical model.Finally,a series of parameter studies were conducted.The results indicate that the optimized distribution of circumferential ribs can significantly enhance the stability of carbon fiber/epoxy AGS conical shells.The present study provides useful guideline for configuration of carbon fiber/epoxy AGS conical shells,as well as an analytical model for calculating the equivalent stiffness and buckling resistance.