Application of stress gradient plasticity model in different passivated problems

In classical plasticity models, the physical length scale is not considered to control the size effects. Strain gradient plasticity models include one or more length scales that control size effects. Stress gradient plasticity model is introduced with a specific physical length scale and does not include any additional parameters. Torsion of a hollow tube, pure shear of a slab, and torsion of a rod with and without passivation is modeled by considering elasto-plastic hardening model. The effects of passivation on material deformation are studied. By increasing the material length scale and keeping the other parameters constant, the average equivalent plastic strain is decreased and the average stress is increased, as well as the hardening rate of the stress-strain curves. The obtained results are compared with the experimental results of Liu et al. (2013) and the results obtained from the theory of strain gradient plasticity for different problems (Niordson and Hutchinson, 2003; Lubarda, 2016; Hua and Liu, 2020). The results of the Stress gradient plasticity model is also compared with the strain gradient plasticity models.

https://authors.elsevier.com/a/1d7XT_3p%7Ev3g78