Construction and Application of DKQ Bending Element

In order to analyze the states of thin-walled structures under complicated loads by discrete Kirchhoff principle, the strain matrix of triangle bending element and explicit area coordinate integral method were discussed in detail.According to variant principle, DKQ (Discrete Kirchhoff Quadrilateral) bending element was constructed.By introducing symmetric and antisymmetric mesh distortion modes, mesh distortion sensitivity analysis was carried out.Through combining DKQ element with planar stress element, quadrilateral plate element used for general thin-walled structures analysis was implemented by finite element program.Numerical test result indicates that when relative offset value varies from-0.18 to 0.18, the deflection maximum errors of antisymmetric and symmetric modes are 1.83% and 0.99% respectively.For a car-body of some subway vehicle, the differences between the analysis values and those obtained by ANSYS are less than 3.5%.The result shows that DKQ bending element is insensitive to mesh distortion and has good convergence capability and accuracy for displacement field.