Geometric nonlinear bending response and buckling of angle-section beams under pure bending

•Nonlinear bending response of angle beams of finite length is investigated.•Influence of section flattening on loading capacity of beams is examined.•It highlights the difference between static and dynamic instabilities.•The solution is validated using nonlinear FEA methods.

In this paper, the geometric nonlinear bending response of angle-section beams of finite length is investigated by using energy methods. The basic assumptions used in the present study are that the total strain energy of an angle-section beam subjected to pure bending can be simplified into a two-stage process. One is the bending response of the two legs behaving as the plate; the other is the overall bending response as a beam with flattened section. The nonlinear bending response is derived by applying the minimum potential energy principle and the corresponding static and dynamic critical moments associated with the section flattening-induced buckling are determined. To validate the analytical solution developed, geometric nonlinear finite element analyses are also conducted. Good agreement between the present solution and the FEA results is demonstrated.