On the ratcheting response of circular steel pipes subject to cyclic inelastic bending: A closed-form analytical solution

• Published in: International journal of mechanical sciences Vol. 117; pp. 243 - 257
• Main Authors: Zeinoddini, M., Mo’tamedi, M., Asil Gharebaghi, S., Parke, G.A.R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2016
• Subjects: Creep (materials); Creep type ovalisation; Cyclic inelastic bending; Cyclic plasticity; Exact solutions; Hardening; Mathematical analysis; Mathematical models; Nonlinearity; Serrated yielding; Steel tubes; Strain ratcheting; Tubes; Strain ratcheting; Creep type ovalisation; Steel tubes; Cyclic plasticity; Cyclic inelastic bending
• ISSN: 0020-7403; 1879-2162
• DOI: 10.1016/j.ijmecsci.2016.09.004

The current paper deals with the cyclic plastic response and strain ratcheting of circular steel tubes under repeated inelastic pure bending. A closed-form solution is proposed for the problem. The cyclic softening/hardening behaviour of the material is modelled using a combined bilinear kinematic/nonlinear isotropic hardening rule. The relative hardening modulus in each half-cycle is considered as an extra state variable to account for the non-fading memory characteristics of the material. The cycle by cycle growth (creep) in the ovalisation of the cross-section is modelled using a modified version of the Bailey–Norton creep law. The solution considers the material nonlinearity, the cyclic plasticity effects and the geometrical nonlinearity due to the ovalisation of the cross-section. The model predictions are examined against a number of available test data on the inelastic monotonic and cyclic bending of tubes and reasonable agreements are observed.