| Cylindrical shell structure is widely used in engineering practice as it has unique geometry characteristic,it is not difficult to make or build and also can bear load to a certain degree at the same time.Cylindrical pressure hull bears different kinds of internal and external load,whose compression is easily influenced by material,geometry,imperfection,structure and so on,which can easily cause structural failure of the shell.Therefore,this paper proposes a longitudinal corrugated cylindrical pressure shell.Adding a longitudinal corrugated reinforcing structure to cylindrical shell can improve the carrying capacity of the cylindrical shell.In this paper,the buckling characteristics of longitudinal corrugated cylindrical shell under uniform external pressure are studied by combining numerical analysis and experimental.The main contents are as follows:First of all,the longitudinal corrugated cylindrical shell is preliminary designed and the geometric parameters of the shell and the corrugated structure are optimized.The Fourier series is used to establish the mathematical model of the longitudinal corrugated cylindrical shell,and the preliminary geometric design of the longitudinal corrugated cylindrical shell structure is carried out accordingly.The influence of different diameter-thickness ratio and longitudinal corrugated connection on the buckling of the shell have been successively discussed through numerical calculation.The results show the buckling load amplification that longitudinal corrugated cylindrical shell is relative to cylindrical shell increases along with the increase of shell diameter-thickness ratio,and the shell buckling load is largest when there is no transition structure at the corrugated joint.Secondly,the analysis of the influence of the corrugated parameters of longitudinal corrugated cylindrical shell have been conducted.The definition of longitudinal corrugation shape parameters is mainly measured by the corrugation width w and the corrugation depth d according to the previous studies.According to the selective wall thickness parameter and the form of corrugation connection,a series of equal volumes with different corrugated shape parameter are designed,and their geometric and numerical models are established respectively.The best corrugation shape of the longitudinal corrugated cylindrical shell is optimized through numerical analysis,which is semi-circle corrugation.On the basis of that,numerical calculations are performed on several equal-volume longitudinal corrugated cylindrical shells with different corrugation numbers,deeply analyze the influence of corrugation number on the buckling of the shell.Thirdly,the comparison of buckling of longitudinal corrugated cylindrical shell and equivalent cylindrical shell are carried out.The longitudinal corrugated cylindrical shell and the equivalent cylindrical shell are designed by using the principle of volume equivalence and the principle of volume-mass equivalence respectively.The linear elastic and nonlinear buckling and the stability of the two shells with initial imperfections are compared and analyzed.The result shows the buckling load of the longitudinal corrugated cylindrical shell is significantly better than that of the equivalent cylindrical shell under the two equivalent conditions.The bearing performance of corrugated shell is more prominent than that of equivalent cylindrical shells although under the condition of defects.Finally,the experiment on the buckling of longitudinal corrugated cylindrical shell and equal volume cylindrical shells is carried out.The resin and metal test models of longitudinal corrugated cylindrical shell and cylindrical shell are fabricated respectively by using 3D printing technology and stamping process.Each test model performs geometric measurement,error analysis and hydrostatic pressure test separately,then compare the numerical calculation results with the test results.The test results show that the average failure load of the longitudinal corrugated cylindrical shell is about 56.8% higher than that of the equivalent cylindrical shell,which means that the ultimate load capacity of the longitudinal corrugated cylindrical shell is significantly better than that of the equivalent cylindrical shell.At the same time,the numerical analysis results of ideal model and scanning model are basically consistent with the experiment results,which prove the effectiveness of numerical analysis method. |
PDF Full Text Request