The Research On Strength And Stability Influenced By The Out Of Roundness Of Pressure Hull

The cylindrical shell is widely used in ship and ocean structures. Because of the inevitable error which was made in manufacturing process, out of roundness presented. Therefore out of roundness, which would reduce the structure bearing capacity, will have the important influence on the stability of cylindrical shell. Thorough theory discussion and analysis were performed on the cylindrical shell with initial distortion, and modeling computation and the contrast analysis were made by general finite element software ANSYS. The main content was as following:1) The energy method was used to derive the theoretical critical pressure formula including the influence of out of roundness to the cylindrical shell stability.2) Finite element software ANSYS was used to calculate the influence of different distribution form of out of roundness to the cylindrical shell's stability.3) The theory solution and model test solution were contrasted and analyzed to evaluate the accuracy of the computational method. The statistical rule of out of roundness in the actual manufacturing process was given out.4) The influence of initial flaw on stability and strength of cylindrical shell was discussed according to the scope of initial flaw. The calculation method which adapted to the project evaluation was established.