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.