Non-Linear Post-Buckling Large Displacement Analysis for Plane Steel Non-Prismatic Members Frames With Flexible Connections

Abstract

Although the joints constitute a small proportion of the total weight of the structure, but they have a comparatively large work ratio, thus the accounted is represent a large percentage of the total cost of framing. In addition, the contact region deformation is sometimes responsible for a significant proportion of the total deviation of the structure and often has a large impact on the distribution of internal distribution of the forces. All real structures show nonlinear behavior when loads and deformations become large enough and the tapered members are also used in several locations in the structural applications such as aerospace structures, bridges, as well, in many mechanical components. It is used to try to meet the architectural requirements for the shape of buildings and to achieve a suitable division of strength and weight. So, the nonlinear post-buckling behavior of plane steel frame under loads was a major research topic. A general formulation of Eulerian is used to analyze the plane frames and it is clear that this method of analysis are be good to use within theory of beam-column. This study is shown that a polynomial modeling of the non-linear moment-rotation curve of steel connection gives excellent results with the exact non-linear moment-rotation curve with a difference not more than (1%) and the effect of the flexible connections must be considered in the analysis because it has significant effect on the behavior of the steel structures and the new modified tangent stiffness matrix which takes into account the two types of non-linearities at the same time (i.e. geometry and connection) and non-prismatic members efficient in giving accurate results of analysis of different types frames with difference not more than (0.5%) compere with the other finite element methods for analysis.

Post Buckling Behavior of Prismatic Structural Steel Members with Semi Rigid Connections

“…(9) shows post buckling behavior of leeʹs frame with semi rigid connection in different load steps. It can be noted that the results of this study show good agreement with the results of Al-Mahdawi [17].Fig. (13) shows the original shape of the frame, the frame at the ultimate load and variation of vertical displacement along the frame.…”

“…This frame was analyzed using variable displacement control (modified displacement control) by Fujii et al [16], using beam-column theory by Al-Mahdawi [17]and using finite element method by Ismael and Salman [18], Ismael and Salman used BEAM188 element to modeling the frame in ANSYS to predict fully load-displacement relationship in post buckling behavior. In this study BEAM3 element was used to modeling the frame and to predict load-displacement relationship until initial peak load in post buckling behavior since BEAM3 is more appropriate with COMBIN14 element to modeling semi rigid connection.…”