Abstract

The object of the study is a cylindrical mesh shell without a regular structure covering, made of carbon fiber composite material. A distinctive feature of this class of structures is the intersection of families of annular and spiral edges. Mesh shells are used as power elements of spacecraft; therefore, when designing them, the main requirements are a reduction in the mass of the structure, high strength and stiffness characteristics. The reduction of the shell mass is achieved by varying and selecting the structural and geometric parameters of the edges. The article considers a set of mesh cylindrical structures of fixed mass. The authors have developed and presented an algorithm for calculating the number of elements of a regular edge structure and calculating the values of geometric parameters of elements of edge families. Two approaches to the formation of rib systems are considered: by changing the heights or thicknesses of the rib structure. A macro has been developed for modeling parametric discrete models of such edge structures in the ANSYS Mechanical APDL software package. When constructing discrete grid models, a one-dimensional two-node finite element BEAM4 was used. The model was rigidly attached at the nodes along the lower edge, and a load was applied to the nodes of the upper edge. Two types of loading were considered. The “nonflight” mode was determined by the axial loading of the shell evenly distributed along the upper edge. The “flight” mode additionally took into account the applied moment. The displacement and deformation fields were calculated numerically in the ANSYS finite element package. The article presents the results of a study of the effect of the density of the rib structure on the stability of mesh shells under static axial loading, natural frequencies, and waveforms. It is shown that, with increasing density, the rib structure becomes thinner. At the same time, the critical load decreases, the values of the natural frequencies of the shells decrease, and the number of waves in the forms increases. The influence of approaches to the modeling of rib structures on the results of numerical calculations is noted.

中文翻译：

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静载下改变肋结构参数时不等网格圆柱壳的应力状态研究及稳定性评估

摘要

研究对象是一个没有规则结构覆盖物的圆柱形网壳，由碳纤维复合材料制成。这类结构的一个显着特征是环形边缘族和螺旋边缘族的交叉。网壳用作航天器的动力元件；因此，在设计它们时，主要要求是减少结构质量、高强度和刚度特性。壳质量的减少是通过改变和选择边缘的结构和几何参数来实现的。本文考虑了一组固定质量的网格圆柱结构。作者开发并提出了一种计算规则边缘结构的元素数量和计算边缘族元素的几何参数值的算法。考虑了形成肋系统的两种方法：通过改变肋结构的高度或厚度。已经开发了一个宏，用于在 ANSYS Mechanical APDL 软件包中对此类边缘结构的参数化离散模型进行建模。构建离散网格模型时，使用一维二维有限元BEAM4。该模型沿下边缘刚性连接在节点上，并将载荷施加到上边缘的节点上。考虑了两种类型的载荷。“非飞行”模式由沿上边缘均匀分布的壳体轴向载荷决定。“飞行”模式还考虑了施加的力矩。位移和变形场在 ANSYS 有限元软件包中进行数值计算。本文介绍了在静态轴向载荷、固有频率和波形下肋结构密度对网壳稳定性影响的研究结果。结果表明，随着密度的增加，肋结构变得更薄。同时，临界载荷减小，壳的固有频率值减小，形式中的波数增加。注意到肋结构建模方法对数值计算结果的影响。