Reinforcement Design And Experimental Study Of External Pressure Conical Shell With Openings

In practical engineering applications,conical pressure vessels have a good streamlined shape and are widely used in the field of marine engineering,chemical reaction vessels and aviation.Conical shell is a common pressure structure of submarine,because to observe the external situation,it is necessary to open an observation window on the shell.In addition,some parts and pipes need to be opened through holes on the pressure shell.Openings will inevitably weaken the overall strength of conical shells,so it is necessary to analyze and study the opening of conical shells.The main contents and conclusions of this paper are as follows:（1）Based on the theoretical specifications of classification societies,two opening models of open conical shells and equivalent open cylindrical shells are constructed to compare and analyze the effects of opening position and opening diameter on the flexural properties of the two shells.The results show that the maximum linear and nonlinear buckling loads of the two shells appear in the region near the opening,which has certain similarity.With the increase of opening diameter,the linear and nonlinear buckling critical load values of both shells show an overall decreasing trend.The load-bearing capacity of the two shells is better when the opening position is 3/6.（2）The effects of opening parameters on the buckling load of a conical shell with an opening are studied by numerical analysis and hydraulic test.And the random forest algorithm is used to construct the prediction model for prediction.The results show that:when the reinforced wall is perpendicular to the bus bar and the opening ratio is less than0.540,the load value reaches the maximum when the opening is in the middle of the bus bar;when the opening is in the middle of the bus bar of the conical shell and the opening rate is less than 0.441,the inclination angle of the wall is near 30°,and the load value reaches the maximum.The correlation coefficient between the predicted value of the model and the finite element calculation data reaches 0.973,which indicates that the prediction accuracy of the prediction model is excellent.（3）Parametric modeling is used to discuss the effects of the three parameters namely,the thickness of the inclined enclosure,the height of the inner wall and the height of the outer wall,and the diameter-thickness ratio on the buckling performance of the single-opening reinforced conical shell.Secondly,an orthogonal test is used to calculate the data and fit a linear regression equation to analyze the influence of the three enclosure parameters on it.Finally,the effects of four different numbers of openings on the buckling properties of conical shells with inclined reinforcement of the perimeter wall are compared and analyzed.The results show that,among the three parameters,the most influential is the thickness t₀ of the inclined perimeter wall,followed by the height h₂ inside the inclined reinforced perimeter wall;when the number of openings in the conical shell reinforcement structure is odd openings,the buckling performance is better than that of double openings and the four openings.