Nowadays the use of thin-walled structures is widely accepted. The main reason for this is low weight and high resistance of these structures. In order to reduce the weight and cost of the structure, cylindrical steel tanks can be made in variable thickness. In general, foundation's settlement occur beneath the reservoir walls due to specific soil properties, which are divided into three general components: 1- Uniform Settlement 2- Tilt Settlement 3- Local Settlement. Among these components, Local settlement has the greatest impact on the reservoir shell. This component can cause large radial displacements, shell buckling and even tank failure. In this research, three steel cylindrical tanks, two specimens of constant thickness and one specimen of variable thickness, are first modeled in Finite Element and then made in the laboratory and subjected to local settlement at the edge of their floor. And the values of settlement, buckling load, final load, stress and radial deformation is compared. The data obtained from the eigenvalue analysis show that the effect of increasing the thickness on the critical buckling load is extremely high and the higher thickness at the lower part of the shell is highly influential. The results of Nonlinear analysis indicate that the behavior of tank with variable thickness is acceptable compared to other samples. Also in all samples, the radial deformation is initially negligible and then increases sharply due to the structural buckling, which is the same for all samples. According to experimental result the out of plane deformation recorded by the transducer mounted at a 45-degree angle indicates that in the samples of constant thickness the values are close together, whereas in the sample of variable thickness the amount of this deformation decreases, which is a positive result. Comparison of the results between numerical and experimental modeling also indicate good agreement between these two methods.

如今，薄壁结构的使用已被广泛接受。造成这种情况的主要原因是这些结构的重量轻且电阻高。为了减轻结构的重量和成本，可以将圆柱形钢罐制成可变厚度。通常，由于特定的土壤特性，地基的沉降发生在储层壁的下方，这些特性分为三个基本部分：1-均匀沉降2-倾斜沉降3-局部沉降。在这些组成部分中，局部沉降对油藏壳的影响最大。该部件可能导致较大的径向位移，壳体屈曲，甚至导致罐失效。在这项研究中，三个钢制圆柱罐，两个恒定厚度的样本和一个可变厚度的样本，首先在有限元模型中建模，然后在实验室中制作，并在其地板边缘进行局部沉降。并比较了沉降，屈曲载荷，最终载荷，应力和径向变形的值。从特征值分析获得的数据表明，增加厚度对临界屈曲载荷的影响极高，而壳体下部的较高厚度则具有很大的影响力。非线性分析的结果表明，与其他样品相比，厚度可变的储罐的性能是可以接受的。同样在所有样品中，径向变形最初可忽略不计，然后由于结构屈曲而急剧增加，这对于所有样品都是相同的。根据实验结果，以45度角安装的换能器记录的面外变形表明，在厚度恒定的样品中，这些值彼此靠近，而在厚度可变的样品中，此变形量减少了，即一个积极的结果。数值模型和实验模型之间的结果比较也表明这两种方法之间具有很好的一致性。