Abstract：The shear lag warping displacement function of the cantilever, top and bottom plate of flange section were assumed. The total potential energy function of the structure was obtained by the assumption. Based on potential various principles, the geometrical nonlinear governing equation of the large curvature thinwalled curved girder was deduced with regarding of the influence of curvature radius change along beam width. The approximate solution was obtained by spline least squares collocation method to deduce the internal force and displacement of the structures under loads. Effect of curvature radius on the structure was also analyzed. The comparison of calculating value with test results illuminates that the proposed method is reliable, and especially that the important force locations of curved box girder cross-section are very close. The results show that the influence of curvature radius change along the beam width on shear lag could be ignored when the ratio of width and diameter is less than 0.1. The shear lag coefficient in each section tends to symmetry gradually with the increasing of the curvature radius， while the torsional angle and the deflection decrease with the increase of their linear elastic scopes in the relationship of torsional angle-load and deflection-load.
陈玉骥, 罗旗帜. 大曲率薄壁曲线梁几何非线性问题的力学模型[J]. 江苏大学学报（自然科学版）, 2011, 32(3): 364-368.
CHEN Yujji, LUO Qizhi. Mechanics model for geometrical nonlinear problem of large curvature thin-walled curved girder[J]. Journal of Jiangsu University(Natural Science Eidtion)
, 2011, 32(3): 364-368.
2011, Vol. 32 
