Numerical investigation of residual ultimate strength of dented metallic pipes subjected to pure bending

A dent is one of the main structural damages that may affect ultimate strength. In this paper, the residual ultimate strength of dented metallic pipes subjected to a bending moment is quantitatively investigated. The numerical model is developed accounting for the variation of the dent length (l_d), dent depth (d_d), dent width (w_d), dent rotation angle (θ_d) and dent location based on ABAQUS Python. The numerical model is validated by test results from a four-point bending test. Subsequently, a parametric investigation is performed on the effects of wave-type initial imperfection, D/t and dent geometrical parameters. It is found that both l_d and d_d have a significant effect on the residual ultimate strength of dented metallic pipes, while the effect of w_d is slight. Finally, an empirical formula with respect to l_d and d_d has been proposed for the prediction of bending moment, which can be deployed for practical purposes.