Self-Equilibrating Element for Second-Order Analysis of Semirigid Jointed Frames

Abstract

An accurate pointwise equilibrating polynomial element with springs connected to its ends to model semirigid connections is derived. The formulated element and coded computer program for second-order nonlinear analysis of flexibly jointed steel frames is employed to study a variety of problems using one element per member, which is not possible by the conventional cubic Hermitian function and most of the currently available elements. When incorporated into a nonlinear-analysis computer program, the versatility of the program is greatly improved as the convergence rate is increased, and the modeling effort for accurate solution is reduced considerably because the element stiffness remains accurate under high axial load. The capability of the proposed element in handling a harsh benchmark problem is also verified in one of the examples.