单轴对称薄壁工字型钢梁稳定性的有限元分析

Finite element analysis of buckling moments of thin-walled beams with nonsymmetrical I-shaped-sections

采用ANSYS有限元分析软件中的板壳单元SHELL63、三维实体单元SOLID45 进行了单轴对称薄壁工字型钢梁的整体失稳分析. 分析结果表明:在单轴对称薄壁工字型钢梁跨高比较大情况下,传统稳定理论和按《钢结构设计规范》中的方法可以较好地预测钢梁的稳定承载力,但在跨高比小于13 情况下,误差仍较大,此时采用《钢结构设计规范》计算稳定承载力并不合适.

A beam is the basic member in structure engineering, especially, applications of thin-walled steel beams is very prevalent in water conservancy and water and electricity, bridge engineering, architecture engineering and so on. Beam sections are made generally into narrow and high shapes; the moments of two principal axes vary greatly. If a beam's span in middle part has no lateral supports or the distance of lateral supports is very large, the loadings reach certain value the maximum stiff master plane may produce lateral displacement and torsion and lose stability. Using the traditional formula in practical engineering is very troublesome, computer finite element program enhances efficiency very much. This paper presents a buckling analysis of thin-walled beams based on the stability theory of shells and analyzes buckling moments of thin-walled beams with nonsymmetrical by finite element program ANSYS using three-dimensional elements SHELL63 and SOLID45. A total of 32 thin-walled beams have been analyzed. We have compared SHELL63、SOLID45 with the academic results adopting finite element program ANSYS. Results indicate that when span-depth ratio is very large SHELL63、SOLID45 can simulate stability calculation of thin-walled beams very well because fewer assumption are used to establish shell buckling theory. Above all, when span-depth ratio less than 13, error is larger, adopting criterion is less appropriate.