The plasticity in the liner is calculated based on layers. When the stresses in a layer exceed the peak stress, they drop to the residual stress. The procedure follows the same approach that is outlined in the book by Owen, D.R.J. and Hinton, E. (1986):
Owen, D.R.J. and Hinton, E. (1986). Finite Elements in Plasticity: Theory and Practice
RS2 does not output the liner strains to interpret.