Abstract
We derive the stiffness matrix of finite element in order to estimate the stress distribution and the stiffness of thin walled curved beam with arbitrary cross section. It is well known that this type beam, which is subjected to bending moment, shows considerable high stress and reduced stiffness due to the effect of wall bending. For example, restricted cases, circular and elliptical tubes, etc., have been treated by analytical way. So, based on the axisymmetric shell theory, at first, the assumed stress "Hybrid" FEM is formulated for arbitrary shapes. It makes us easy to carry out the parametric examinations. Second, since we want to take an ordinary beam for a member of structure as well as thin walled curved one, we could consider how to describe the characteristics of the member, here. Several representative cases are computed, but we find out that the reduced stiffness is more serious under the out-plane bending than in-plane.
