Theoretical And Experimental Study On The Buckling Of Cylindrical Shell

The submersible is the visual plant for marine research and marine resources development.The pressure hull as a key equipment to resist underwater high pressure,its structural design is particularly important.Cylindrical shell is widely used in submersible because of its relatively simple production and convenient installation of internal space.Therefore,it is of great significance to carry out theoretical and experimental research on cylindrical shells,to explore the factors affecting the critical buckling pressure of cylindrical shells,and to improve the accuracy of the theoretical and numerical analysis for the prediction of critical instability pressure.The main contents are as follows:(1)The strength and stability of the cylindrical shell are checked with the submersible specifications of China Classification Society(CCS2013)and the American submersible specifications of American Bureau of Shipping(ABS2012),and the reasons for the difference between the two kinds of design specifications are analyzed by the calculation results.The finite element method is used to analyze the cylindrical shell model with different rate of L/R,and the results of the finite element method are compared with the results of the two design specifications,and the influence of the length of the section to the error between the two results is analyzed.(2)In this paper,the influence of four different forms of ring stiffener,rectangular stiffening ring,T stiffening ring,L stiffening ring and I stiffening ring,on the strength and stability of cylindrical shells is revealed under the same moments of inertia.To ensure the constant moment of inertia of the ring stiffener,the moment of inertia of each ring stiffener is redistributed on the basis of the radial displacement of the shell,and two methods of formula calculation and finite element calculation are used to analyze the changes of the strength and stability of the cylindrical shells,as well as the effect on the section area and volume of the ring stiffener.(3)Two groups of equivalent cylindrical shell model experiments are arranged,one group is non-stiffener cylindrical shell with different rate of L/R and another is cylindrical shells of equal length with different number of ring stiffeners.Through two sets of experiments,the errors of the three calculation results,formula,finite element and experimental,are studied,and the influencing factors that may lead to errors are analyzed.Comparing the error between the three-dimensional scanning model and the theoretical model considering the initial imperfection,the adaptability of the theoretical model with defects is explored.(4)The non-uniform arrangement of the inertia moment is applied to the design of the pressure cylindrical shell of the underwater space station with a working depth of 650 meters.The influence of uniform and non-uniform arrangement of ring stiffener on strength and stability of cylindrical shell is compared,and the design of the shell structure is optimized by comparison.