结构动力特性分析中的圆角建模方法

针对薄壁结构中存在大量的圆角，提出了运用梁单元与壳单元组合的建模方法对圆角进行等效建模。通过分析圆角对薄壁结构的刚度贡献，提出圆角对结构刚度的贡献分为面内刚度贡献和面外刚度贡献。圆角对面外刚度的贡献与梁的作用等效，通过运用扭转相关理论推导出等效梁单元的截面参数。对于圆角的面内效应，运用壳单元对其进行等效建模，采用平面应变状态假设，将三维结构简化为二维结构。在平面内，通过刚度等效原理计算出壳单元的等效厚度与弹性模量。通过2个实例验证了圆角建模方法的正确性与准确性。

Fillet modeling method in analysis of structural dynamic characteristics

In view of the large number of rounded corners in thin-walled structures, the equivalent modeling method is presented based on the combination of beam element and shell element. Through the analysis of the contribution of the fillet to the stiffness of the thin-walled structure, the contribution was divided into in-plane stiffness contribution and out-of-plane stiffness contribution. The contribution effect of the fillet to the out-of-plane stiffness is equivalent to the beam. The section parameters of the equivalent beam element were derived by using the theory of torsion. For the in-plane effects of the fillet, the equivalent model was established by using shell element. The three-dimensional structure was simplified to a two-dimensional structure by using the plane strain state assumption. In plane, the equivalent thickness and elastic modulus of shell element were calculated by the equivalent stiffness principle. The correctness and accuracy of the modeling method are verified by two examples.