Research On Buckling Analysis Of Stringer-stiffened Thin-walled Cylindrical Shell Under Axial Load

Thin-wall cylindrical shells are widely used in chemical,aerospace and civil engineering.The large diameter and thickness ratio could cause buckling of this structure under axial pressure.One of the useful ways to improve its ability of resisting axial buckling is to arrange stringers and rings on the shell surface.Experiment and nonlinear FEA methods are used to investigate the buckling behavior of stringer-stiffened thin-wall cylindrical shells under axial pressure.The main works are as follows:(1)The geometrical morphology measurement of thin-wall cylindrical shell specimens are carried out by using the axial buckling test platform.Based on the measured data,the results of three nonlinear numerical simulation methods-Riks method,nonlinear static method and explicit dynamic method-are compared and analyzed.Meanwhile,the axial buckling suppression experiment are executed.By comparing the results of experiment and finite element simulation,a method that can accurately simulate the axial buckling behavior of thin-wall cylindrical shells with initial imperfection is set up.(2)In order to determine proper parameters of test specimens,the preliminary analysis of axial buckling loads of stiffened thin-wall cylindrical shells is carried out by using linear FEA method.The geometrical morphology measurement and axial buckling suppression experiment of stringer-stiffened thin-wall cylindrical shells are carried out to research the effect of stringer on thin-wall cylindrical shell.The experiment results and nonlinear FEA results are compared and analyzed,both of them show that stringer can improve the axial buckling loads of thin-wall cylindrical shell.And with the increase of the number of stringers,the axial buckling critical loads of structure also increase.(3)The influence of stringer character parameters,such as the inner and outer arrangement way,height and width ratio,quantity and area,on the buckling critical loads of thin-wall cylindrical shells with initial imperfection and constant structure volume is researched by nonlinear static finite element stimulation method.Based on the orthogonal test design method,an optimized numerical simulation scheme is made to investigate the significance level and the degree of influence of stringer and cylindrical shell character parameters on the axial buckling critical load of thin-wall cylindrical shell.The result shows that the quantity,area and height and width ratio of stringer have great influence on axial buckling critical load,while the diameter and thickness ratio and height and diameter ratio of cylindrical shells have little influence.(4)Taking the 1000 m3 fixed-roof storage tank as an example,the design of stringer arrangement is conducted,the numerical simulation result verifies the validity and rationality of the conclusion about choosing stringer character parameters.