FURTHER RESULTS ON THE RESPONSE OF SPHERICAL INFLATABLES UNDER AXISYMMETRICAL HYDROSTATIC LOADS

The large deflection and stability behaviour of spherical inflatables subjected to axisymmetric hydrostatic loading and with geometries rang ing from low-profiled to very lofty shapes, is treated. Support settle ment and vertical contact along the axis of symmetry for very lofty st ructures and under large deflections are also admitted. The deflected shape of the membrane in the pond region is defined by a set of integr o-differential equations of the Volterra type, the solution of which r equires numerical methods. The formulation involves an Eulerian descri ption and assumes the membrane to be inextensible. An iterative scheme based on a Runge-Kutta IVth order integration technique incorporating a special FORTRAN computer code is used in obtaining numerical result s. Detailed calculations were carried out for a range of densities fro m gamma = gamma R(0)/(P0) = 2.78 to 30.0, the former being the critica l density below which no pending is possible. Special attention was pa id to loads of densities gamma = 2.78, 4.55 and 9.0. Results are prese nted in nondimensional form on graphs and figures. They indicate and c onfirm that a small initial pond will grow and ultimately result in an inverted configuration in which the structure acts as a sack filled w ith liquid.