A141 Rigid plastic flow rule inversion
Rearranging the first of equations (A1.29) gives
In principle, this can be used directly to determine the deviatoric stress field from a given strain increment field. However, the right-hand side is non-linear in the strain increments as both s and de depend on them. Practical rigid plastic finite element methods (Section A1.5) seek actual strain increment fields from initial guesses, by iteration. For efficiency of operation, they use a linearized form of equation (A1.33), to calculate variations of s'j caused by variations in strain increment. They must also find some way to estimate hydrostatic stresses, not involved in yielding. Both these practical matters are introduced in this section.
Post a comment