Study On Stability Of Cylindrical Shell With Nozzles Based On The Fourier Series Model

Under external pressure,instability failure is one of the main failure modes of the cylindrical shell.It has been found that buckling pressure of cylindrical shells is closely related to its geometrical size,geometrical imperfection and material properties.When these factors are determined,the stability of the shell is damaged by the opening of the cylindrical shell,especially under the large opening,the buckling pressure of the cylindrical shell will drop significantly.At the same time,the instability pressure of the cylindrical shell can be improved by the effect of nozzles.At present,further research is needed on the effect of opening and connection on instability pressure of cylindrical shell.In this paper,based on the Fourier series model,study on the effect of opening and nozzle on the buckling pressure of cylindrical shell by finite element simulation,and verified the simulation method and results by external pressure experiment.Using ABAQUS finite element simulation software and build the Fourier series model of the cylindrical shell with nozzles by python script.Research the weakening ability of the opening and the improving of nozzle on the stability of the cylindrical shell under the different geometrical dimensions and geometric defects.The results of the study show that the effect of the opening and nozzle on the instability pressure of the cylindrical shell depends not only on the size of the opening hole and the thickness of the nozzle,but also on the stability of the cylindrical shell itself.The greater the stability of the cylindrical shell itself,the effect of opening and nozzle on its stability is more significant.Conducted the external pressure experiment of cylindrical shells with nozzles.Analysis the effect of nozzles on the instability of cylindrical shell by the external pressure experiment.Based on the instability morphology and strain data of the sample,it is concluded that the effect of the nozzle on the stability of the cylindrical shell is local.However,with the big opening,it will affect the instability position to some extent,it is resulting in that position unable to form waveform.Scanning the samples of external pressure experiment by 3D laser scanner and obtained the scanning model.The numerical simulation results of the scanning model are in good agreement with the experimental data,which verifies the correctness of the numerical simulation method.In this paper,the stability of the external pressure of a cylindrical shell with an opening was studied by numerical simulation and experiment,considered the real geometric defects under the premise of nozzle wall reinforcement method is studied in the opening to take over the cylindrical shell structure for reinforcing ability stability under external pressure,and verified the feasibility of studying the stability of the external pressure of a cylindrical shell with nozzles by using the Fourier series model.Because the stability of the cylindrical shell is strong,the stability of the cylinder shell is weakened greatly when the hole is opened.As for this kind of structure,it is necessary to consider the larger safety margin to meet the engineering requirements when calculate the reinforcement of the hole.