储运设备中的旋转壳在任意载荷下的非线性分析

摘要

薄壁旋转壳是一类在油气储运设备中广泛出现的结构，如储罐及其弹性罐顶、柔性波纹管和薄壁管道等。针对这类结构往往具有承受复杂的非轴对称载荷的特点，文章基于Sanders非线性薄壳理论，对油气储运设备中的一类旋转壳结构的非轴对称几何非线性特性进行了分析。利用旋转壳的几何轴对称性，用截锥单元对其进行了有限元离散，而后将所有物理量，包括非线性耦合项，均沿环向展开成Fourier级数的形式，并借鉴Ball的思想，引入“伪载荷”的概念，通过适当的三角恒等式将非线性耦合项处理成“伪载荷”，由此建立起一种形式简单、易于实施的迭代格式。文末的两个算例模拟了储罐及其顶盖在风载和地震载荷作用下的力学特性。%Thin revolving shell is a kind of structure widely found in oil and gas storage and transportation equipment,such as storage tank and its elastic dome,flexible corrugated pipe and thin wall pipeline,etc.In light of that such a kind of structure is of the property of bearing complex non-axisymmetric loads,the non-axisymmetric geometric nonlinear properties of this kind of revolving shell structure in the oil and gas storage and transportation equipment are analyzed on the basis of Sanders nonlinear thin shell theory.By use of the geometric axisymmetry of the revolving shell,its finite element discretization is caried out with the conical frustum element.Then all physical variables,including nonlinear coupling term,are expanded along a circumferential directicn to constitute Fourier series.According to Ball's thought,the nonlinear coupling term is treated as “pseudo load” by appropriate trigonometric identities,thus setting up a simple and facile iterative format.The mechanical characters of storage tank and its dome under wind and seismic loads are simulated by applying two examples.