Design of filament-wound isotensoid pressure vessels with unequal polar openings

Previous studies on filament-wound isotensoids are mostly based on geodesic winding. However, the geometry of geodesics is certainly limiting the available design space. A typical restriction is the inability to create isotensoids with unequal openings at both ends. In this paper, a simplified method for designing isotensoid pressure vessels with unequal polar opening is outlined, using non-geodesic trajectories. Firstly we present the non-geodesic equations on general shells of revolution. Next, a direct relation among the shell curvatures, roving force, internal pressure and slippage coefficient, as a basis for determining non-geodesics-based isotensoid shapes, is provided. The governing equations for specifying meridian profiles are derived in terms of the slippage coefficient. The meridian profiles of non-geodesics-based isotensoids corresponding to various opening radii and slippage coefficients are determined, and the performance factors of the obtaining domes are calculated to demonstrate the effect the application of non-geodesics has on the structural efficiency. A stable and easily accessible solution procedure is proposed to determine the slippage coefficients fulfilling the winding requirements. Results show that the present method is suitable for the design of isotensoid structures with unequal polar openings. Results also indicate that the non-geodesics-based isotensoid domes show better performance than the geodesic–isotensoid.