Study On Structural Stability Of Tower Equipment Under Non-pressure Loading

In this paper,Istudy the buckling of single cylinder based on Eurocode 3 standard,and mainly consider the axial load and shear load.The consideration of the influence of cylinder defects in the standard mainly focuses on three kinds of roundness,dent and eccentricity tolerance.And according to the worst one,the manufacturing quality parameter is substituted into the formula calculation and regarded as the defect effect.But it does not reflect the impact of uncertainty in the actual geometric defects.Therefore,this paper will use the "consistent defect mode method" and the GMNIA(double nonlinear analysis with defective geometric material)related criteria given in the standard for finite element analysis,and compare the results obtained by the two.The results of comparative analysis show that the results obtained by using finite element analysis based on the nonlinear geometric and nonlinear material with defects are generally lower than the standard formula method,but the difference between the two results is generally about 10%.At the same time,there is also a problem.When the cylinder with axial load is used to perform the "consistent defect mode" analysis with the first-order instability mode,the results of the short cylinder have a large deviation,and the ANSYS software simulation results.The result of ANSYS is much more conservative.To a certain extent,the GMNIA analysis results are credible.In the comparative analysis,the length of the cylinder is represented by the dimensionless constant ?,and its value is controlled by two parameters of l/r and r/t.The formulas using the instability analysis and the results of the finite element method are more affected by the parameters.For short cylindrical shells with axial compression,the main failure mode is not instability.For long cylindrical shells,the greater the value,the lower the sensitivity to the initial defects of the shell.In this paper,a set of comparisons between the new version of the 2017 standard and the old version of the standard is made.The standard changes the calculation formula of the instability parameter in the axial instability.The comparison shows that the new standard improves the characteristic instability load R_k of the axial compression shell.In other words,the safety range under axial compression is increased,and the difference between the two results increases as r/t increases.