Loads in circular frames due to hydrostatic pressure
Abstract:ESDU 05004 presents graphs which provide the direct force, shear force and moments in circular frames arising from hydrostatic pressure. The level of the fluid giving rise to the pressure loading is defined by the angle between the top of the frame and the surface of the fluid and curves are provided for 12 separate fluid levels over the range 0° to 165°. The curves in the figures were derived using the classical energy method of analysis and Engineer's Theory of Bending on the assumption that the frames are, or may be considered to be, relatively very stiff. Frames may be considered very stiff when located centrally in an array of many similar frames, all equally loaded. It is also assumed that the flexural stiffness of the frame is constant around its circumference; a continuous or frequent load-carrying attachment exists between the skins/stringers and the frames; the stringers provide the principal load-spreading mechanism; and the difference between the radius of the shell and the radius of the frame measured to the centroid of the frame section is negligible. This last assumption means that the total amount fuel in the tank is underestimated slightly and therefore a fuel volume correction factor is employed to take account of this. A worked example illustrates the use of the figures.
|Data Item ESDU 05004|