A Motion Process for Large Displacement Analysis of Spatial Frames

Abstract

A motion process of a spatial beam element which can retain the continuity of spatial frames at rigid joints is poroposed to remove the restriction of small rotations between two successive increments for large displacement analysis of spatial frames using a corotational formulation combined with incremental-iterative methods. Two different strategies are proposed to determine the current configuration. The element formulation is derived based on the small deflection beam theory with the inclusion of the effect of axial force in the element coordinate system which is determined by the locations of end nodes and the orientations of end cross sections of the beam element. The element deformations are determined by rotations of end cross sections relative to the element coordinate system. An incremental-iterative method based on the Newton-Raphson method combined with are length control is adopted. Numerical examples are presented to demonstrate the accuracy and efficiency of the present method.