A FLEXIBILITY BASED BEAM ELEMENT WITH MESHED SECTIONS

A new beam element based on distributed plasticity and flexibility theory is presented for material nonlinear analysis of frame structures, In this formulation, the sections at the axial quadrature points of beam element are discretized into plane isotropic elements, and the stress distribution on the sections is described with the stresses at quadrature points in the mesh. The stiffness matrices of the sections are calculated by integration of the stress-strain relations of material on the meshes. The flexibility matrix of the element is also formed by integration of section flexibility matrices with force-interpolation functions, and then is inverted into the element stiffness matrix. The advantages of the flexibility method are discussed in the paper. Finally a numerical example is given for nonlinear analysis of a beam to illustrate the efficiency and accuracy of the method.