Analytical Method Research On Stiffened Prismatic Shells And Related Software Development

The prismatic shells refer to the shells which are composed by the cylindrical shells of different curvature. The cylindrical shell curvature trend to infinity is a plate, broadly said, plate is a peculiar kind of cylindrical shell. Therefore, the structure which is composed by cylindrical shells or plates is called prismatic shells. When the cylindrical shells or the plates of the prismatic shells either have longitudinal or transverse stiffeners, this kind of structure is called stiffened prismatic shells.An analytical method for strength analysis of stiffened prismatic shells and a software development based on this analytical method are mainly researched in this dissertation.The equilibrium differential equations expressed by the displacements of shells for stiffened cylindrical shells are built through introducing the Heaviside step function to describe the exact position of each stiffener derived from the moment theory of shells. Then the stiffened shell can be computed as an unstiffened shell where not only do the external loads act, but also assumed load at each stiffener position act, in consideration of the effect of the stiffeners as loads acting on the shells. So the general solutions of the equilibrium differential equations include the homogeneous solutions, special solutions under the external loads and the effect of the stiffeners.The equilibrium differential equations are solved with the displacements being developed using Fourier series expansion and introducing Green function, and the stresses expressions can be gained based on the displacements expressions. Then the unknown constant coefficients in the displacements and the stresses expressions can be confirmed according to the boundary conditions. Therefore the problem of the strength analysis of stiffened cylindrical shells can be solved. Software development based on the research above is presented in details in this dissertation, some key technologies during developing process such as structured analysis, data flow diagram, modular structure chart, core calculation program, user interface and so on are included. Then by using VC++, Fortran and Matlab mixed programming technology, a software to solve the strength analysis of stiffened shells is developed, whose validity is verified by solving an example and comparing the results with Patran solution.