Portal Frame As A Whole When Considering The Skin Effect By The Force Performance Analysis

Profiled steel sheet has a high shear resistance capacity in plane in light steel structures. It participates in mechanical performance of the whole structure, strengthens the main structure and promotes the structrues'spatial integrity, and that is called sheeting diaphragms effect. At present, profiled steel sheet is still just regarded as part of maintenance structure in our country; its contribution to the whole structure mechanical performance has always not been taken into account, which is not consistent with the actual mechanical performance and is a huge amount of waste. However, with the widely using of light steel structure and growing competition in market, sheeting diaphragms effect has drawn more and more attention of the public.This paper applies finite element analysis software ANSYS to analyze mechanical performance of portal frame structure, considering the sheeting diaphragms effect.At first, the principle of equating profiled steel sheet with orthotropic plate has been discussed specifically, whereby obtained specific methods of calculating some parameters which are required in modeling the structure through ANSYS, including E_x,E_y,μ_x,μ_y,G_eff, And the process of calculating these parameters has also been shown in this paper.Secondly, two models of different type has been set up by using a parametrically design language, called APDL. One is a single frame model built not considering sheeting diaphragms effect. The other is portal frame structure model entirely built taking into sheeting diaphragms effect account, moreover, changing the parameters when doing different analysis, comparing their mechanical performance on various occasions.Finally, based on the result of the structure modeling, I have analyzed the effect of gable supporting and the rigid frame quantities on the distance of column top when considering sheeting diaphragms effect, compared the conditions of the inner forces in the middle rigid frame and the gable supporting bars on different occasions: considering and not considering sheeting diaphragms effect, analyzed the change rule of inner forces in the middle rigid frame and the influence of sheeting diaphragms effect on the inner force of gable walls, and summarized laws in order to reach some suggestions for the reference of engineering practice.