Analysis And Comparative Study Of Static And Dynamic Characteristics Of Orthotropic Circular Cylindrical Shells

Shell structures have been widely used in so many engineering areas; it is interesting and challengeable to study the static and dynamic characteristics of shells. Brief reviews about elastic stability, free vibration, transient dynamic response and harmonic dynamic response of circular cylindrical shells are given first.According to Flügge shell theory, the equations for orthotropic circular cylindrical shells under external hydrostatic pressure are given. A characteristic equation for stability can be obtained for both simply supported at the ends. Divergence loads of shell are calculated from this equation. Jacobi method is used to solve this eigenvalue problem. The effects of orthotropicity, L/R ratio and h/R ratio on the divergence load are discussed in detail. Love-Timoshenko shell theory and Donnell shell theory are also used to calculate the same example. The differences of equilibrium equations, expressions of forces and moments of these 3 theories are given in tables. The accuracy of these two theories is examined in this paper. An analysis is presented for the free vibration of an orthotropic circular cylindrical shell subjected to hydrostatic pressure. Based on Flügge shell theory, the equations of free vibrations of an orthotropic circular cylindrical shell under hydrostatic pressure are obtained. For shear diaphragms at both ends, the resulting characteristic equations about pressure and frequency are given. The effect of shell's parameters (L/R, h/R) and material properties on the free vibration characteristics have been studied in detail. Differences between Love-Timoshenko, Donnell equations and that of Flügge theory are examined too.A study for an orthotropic circular cylindrical shell subjected to axial load is present. The effect of shell's parameters (L/R, h/R) and material properties on the free vibration characteristics have been studied.Following Flügge's exact derivation for the buckling of cylindrical shells, the equations of motion for dynamic loading of an orthotropic circular cylindrical shell under external hydrostatic pressure have been formulated. The normal mode theory is used to provide transient dynamic response for the equations of motion. The effect of shell's parameters, external hydrostatic pressure and material properties on the shell response has been studied in detail. A part of tables and figures are given. The responses of displacements, strain and stress are obtained for the area of impact, while those outside the area of impact are also calculated. The accuracy of normal mode theory and Timoshenko shell theory are examined in this paper.The harmonic responses of an orthotropic circular cylindrical shell under external hydrostatic pressure are studied. There is a slight shift in the locations of the resonant peaks, an example is illustrated for this phenomena. The resonant response of displacements and strain are obtained.