有限元法研究闭口薄壁杆件约束扭转

Torsional analysis and application of thin walled bar with closed profile

基于乌曼斯基薄壁杆件约束扭转理论,利用刚性周边假定建立了闭口薄壁杆件约束扭转分析的一维离散有限元方法.同时利用ANSYS大型有限元软件作对比研究,分析了薄壁箱型梁的截跨比、截面相对厚度等几何特征参数对箱梁扭转变形的影响,并发现这两个参数的取值上限可以从0.1分别扩大到0.15和0.24.算例显示:一维有限元法不仅保持了很好的计算精度,而且计算模型更加简单、离散未知量大大降低.

The one-dimensional finite element model is presented for torsional analysis of the thin walled bar with closed profile with restrained torsionbased on the Umanskii theories of thin-walled bar. The ANSYS package is also employed to compare the accuracy and flexibility of the FEM model presented in this paper. The example shows that the results yielded by the one-dimensional FEM agreed satisfactorily with those obtained by analytical method and the ANSYS package. It can also be concluded that parameters including the relative thickness and the ration of the half of diagonal to span of the box girder can be extended from 0. 1 to 0. 15 and 0. 24 respectively, under which conditions the Umanskii theories can still keep effective.