A.I. Mousa
The University of Gaza, Palestine
M.H. El Naggar
The University of Western Ontario, London, Canada
ABSTRACT
A
new spherical rectangular finite element based on shallow shell formulation is
developed in this paper. The element has six degrees of freedom at each corner
node, five of which are the essential external degrees of freedom and the
additional sixth is associated with the in-plane shell rotation. The
displacement fields of the element satisfy the exact requirement of rigid body
modes of motion. The element is based on independent strain assumption insofar
as it is allowed by the compatibility equations. The element developed herein is
first validated by applying it to the analysis of a benchmark problem involving
a standard spherical shell with simply supported edges. A reliable finite
element package program, ANSYS, is used for structural analysis. The results of
the analysis showed that reasonably accurate results were obtained even when
modeling the shells using fewer elements compared to other shell element types.
The element is then used in a finite element model to analyze cross shaped
spherical roof structures. The distribution of the various components of
deflection and stress is obtained. Furthermore, the effect of introducing
circular arched beams as stiffeners spanning the two diagonally opposite end
corners is investigated. It is found that the stiffeners reduced the deflections
and the stresses in the roof structure by considerable value.