دانلود رایگان مقاله انگلیسی مقطع موثر ستون فولاد سرد شده تحت فشرده سازی محوری - اشپرینگر 2018

Abstract

The compressive resistance of cold-formed steel (CFS) section may be governed by local, distortional or overall buckling and any apparent interaction between these modes. A new inventive stiffened CFS section is elected in this study, selected cross sections geometries and lengths are chosen such that all the types of buckling modes are met with. Buckling plot is plotted using linear elastic buckling analysis software (CUFSM). Using the test results obtained in the literature, the developed finite element model is calibrated and furthers a total of 126 parametric study is conducted such as a consequence of dimensions and the length of the cross section, thickness and yield stress. The FEA included relevant material and geometric imperfections. All the columns are analyzed under pin end conditions with axial compression. The analysis results demonstrate that the DSM equations generally assess the strength of stiffened section conservatively. Modifications to the DSM equations are recommended to evaluate the strength of stiffened section more precisely.

Summary and Conclusions

This study deals with the theoretical and numerical investigation on the ultimate strength and behaviour of pinned end new inventive stiffened CFS section. Numerical investigation is performed by means of the commercial software ANSYS. The numerical model, including the material and geometric imperfections, has been calibrated against the test results obtainable from the literature. Theoretical analyses are carried out by using the Direct Strength Method of specifications for cold formed steel structures. Buckling plot is plotted using linear elastic buckling analysis software (CUFSM). A total of 126 systematic parametric studies is performed using the confirmed FEM. The conclusions of the study are summarized as follows:

• FEA predictions provide the good agreement with the test results.

• Stiffened element at the flanges increases the torsional rigidity of the unstiffened element and intermediate stiffener on the web performed well against local buckling.

• Thickness and yield stress significantly affect the strength and behaviour of the column. Similarly, lip size and depth of the section, size of intermediate stiffener adversely affects the strength of a long column.

• The existing DSM underestimates the ultimate loads of new inventive stiffened CFS section and therefore modification factor is proposed for the proposed section. The modification factors provide better results to the experimental results.