Momentless design of variable stiffness composite cylindrical vessels with elliptical heads

Abstract Membrane stress state is favorable for pressure vessels to resist internal pressure since the stress through shell thickness is constant. However, bending stresses resulted from bending moments of pressure vessels will destroy the favorable membrane stress state leading to nonuniform stress through shell thickness. Thus, suppressing bending moments in pressure vessels will be an efficient way to achieve improvement of load carrying capacity. A momentless design of variable stiffness composite cylindrical vessels with elliptical heads which are widely used in engineering has been presented in this study. The momentless governing equations concerning both the elliptical head and junction region of the pressure vessels under uniform pressure are derived. Numerical analyses are carried out on the pressure vessel models with different configurations. The variable angles of fiber orientations over these models are explicitly provided. The stress resultants and deformation behaviors together with the curvature changes of these models have been checked and compared. Results show that based on the variable fiber angles over the structure obtained from the presented mathematical design methodology, the bending moments are successfully suppressed in the variable stiffness composite pressure vessels . The momentless design method will ensure the pressure vessels to service in an efficient membrane state.