考虑蒙皮效应的冷弯薄壁型钢檩条稳定性分析

RESEARCH ON STABILITY OF COLD-FORMED THIN-WALLED STEEL PURLINS CONSIDERING DIAPHRAGM EFFECT

轻型门式刚架结构中围护结构具有提高整体结构刚度,参与结构整体受力的作用,即蒙皮效应。目前我国相关规范中对蒙皮参与结构受力的贡献很少考虑,而考虑蒙皮效应的设计将使得结构的受力更加符合实际情况,从而更加经济合理。利用有限元软件ANSYS,通过改变约束条件以考虑屋面板压型钢板的蒙皮效应对冷弯薄壁型钢檩条的稳定性作用;利用控制变量法,研究了蒙皮板厚度对檩条稳定承载力的影响。结果表明:考虑蒙皮的侧向檩条约束能有效增加檩条的稳定性;蒙皮厚度对檩条的屈曲荷载影响可以忽略。但布置拉条后,可使檩条的弯扭屈曲承载力有明显提高。

The enclosure parts in portal frame structure play the role of improving the whole stiffness of the structure and engaging in the whole structural behavior,which is called diaphragm effect. For now,the codes in our country take little consideration of the contribution of skin to the structure. The force analysis of the structure will be in accord with real situation and the results will be much more economical and reasonable considering the diaphragm effect in the design. The influence of the presence of the skin on the stability of the purlins was studied by changing the constraint conditions in the paper by using ANSYS. And the effects of the thickness of the skin on the stability of purlin were studied by using control variable method. The results show that considering the lateral restraint of the skin to purlins can effectively increase the stability of purlins,and the impact of skin thickness on the buckling load of purlins can be ignored. But lateral-torsional buckling resistance of the purlin can be obviously improved by using tension bar.