【作者】 李国俊；

【导师】 何保康；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2007， 硕士

【摘要】 冷弯薄壁型钢构件呈现高强、薄壁的发展趋势，其截面形式越来越复杂，屈曲形式除了整体屈曲和局部屈曲外，还有畸变屈曲模式。这些构件很难用传统的有效宽度法进行计算。直接强度法作为一种全新的设计方法，它采用毛截面几何特性进行计算，从而避免了复杂截面有效宽度法的繁琐计算，同时考虑了畸变屈曲的影响。本文采用直接强度法计算了32根截面厚度t=0.6mm、长度为400～2160mm的方形试验截面，并与试验结果进行对比，结果表明：直接强度法可以用于高强轴心受压方形截面构件的承载力计算。在把试验截面等效成腹板中间加劲方形截面的基础上，用直接强度法计算了等效截面构件的承载力，并与试验构件进行了比较，进一步验证了上述结论。用直接强度法进行计算时，关键是求解截面局部屈曲应力f_ol。本文在有限条理论的基础上，采用有限条程序CUFSM计算截面的局部屈曲临界应力。通过对不同宽度、不同加劲高度的腹板中间加劲方形截面局部屈曲临界应力进行计算研究和回归分析，给出了该类截面局部屈曲临界应力f_ol的实用计算公式，供设计计算参考。更多还原

【Abstract】 Cold-formed steel has a tendency to high strength, thin-wall and complex sections. Besides overall buckling and local buckling, distortional buckling is also an existing buckling mode. It is hard to use Effective Width Method （EWM） to calculate the ultimate bearing capacity of high strength cold-formed steel with stiffened elements. However, as a newly developed design method, Direct Strength Method （DSM） takes distortional buckling into consideration and avoids calculating effective width of the complex section for making use of geometric properties of gross section.A total of 32 high strength cold-formed steel squared axial compression columns with section thickness t=0.6mm and a range of lengths from 400mm to 2160mm were calculated by DSM. Comparing the calculated results of DSM with the test results, this paper drew a conclusion that DSM could be applied to calculate the bearing capacity of high strength cold-formed steel squared axial compression columns. The tested section was equaled to squared section with intermediate steiffeners on the web. The bearing capacity of equivalent section specimens was calculated by DSM and the results were compared with the results of test specimens, which further proved the above conclusion.The key point of using DSM is to calculate the local buckling stress f_o1 of the section. Based on the theory of finite strip method, software CUFSM was used to calculate the local buckling stress of the section. After calculating local buckling stress of many squared section members with different width and different height of stiffener, this paper gave a practical formula for the calculation of local buckling stress f_ol of this kind of section through data regression, which could be used as a reference in design calculation.更多还原