EFFECT OF SUPPORT CONDITIONS IN LIQUID-FILLED SPHERICAL VESSELS .1. LIMITING RING-BEAM STIFFNESSES

Spherical vessels are widely used for the containment of liquid on account of their efficient shape. It is well known that the membrane hypothesis, while providing a satisfactory estimate of stresses in regions of the shell remote from the support, becomes inadequate in the support zone, since a realistic assessment of stresses there has to take into account bending effects. Such localized effects depend on the kinematic constraints imposed on the shell by the support, and this two-part study aims to establish the effect and efficiency of the various types of constraint by reference to the ensuring total-stress and total-displacement patterns throughout the domains of the spherical vessel. In this Paper, four possible combinations of limiting (i.e. zero of infinite) ring-beam stiffness (viz. axial (hoop) and torsional (rotational)) are investigated for the usual case when the vessel is supported on vertical columns. Through relevant numerical examples, the role of the torsional stiffness of the support-often less predictable than its axial correlative-is clearly brought out, enabling this design uncertainty to be largely bypassed.