[2] It is used in several commercial finite element codes, and is named after R.W.
The fundamental idea of the approach can already be found in a paper by De Souza Neto et al. from 1994.
[3] The basis of pseudo-elastic material models is a hyperelastic second Piola–Kirchhoff stress
, which is derived from a suitable strain energy density function
: The key idea of pseudo-elastic material models is that the stress during the first loading process is equal to the basic stress
is multiplied by a positive softening function
in the history of the material: It was shown that this idea can also be used to extend arbitrary inelastic material models for softening effects.