AXISYMMETRICAL BUCKLING BEHAVIOR OF TRUNCATED SHALLOW SPHERICAL-SHELLS SUBJECTED TO LINE MOMENT LOADS

This paper is concerned with the nonlinear stability of simply support ed shallow spherical shells with a center hole under the action of a u niformly distributed line moment along a circle concentric with the sh ell boundary. A set of truncated monomials have been used in represent ing various discontinuous distributions in order to simplify formulati ons. We have computed the load-deflection curves, buckling loads, radi al membrane forces and the critical geometrical parameter K-c for shel ls with various center-hole radii. Our numerical results show that (1) both the initial shell stiffness and the buckling load are decreased due to the presence of a center hole with a free boundary. If the hole edge is reinforced with a rigid ring, the truncation not only raises the initial shell stiffness and the buckling load of the shell but als o its critical geometrical parameter K-c. The effects of the truncatio n increase upon increasing the radius of the center hole; (2) for shel ls with large geometrical parameter K, the radial membrane forces at c ritical buckling become partly tensional and the buckling load will be almost unaffected by the truncation if the center hole is situated in side the tensile region.