| (i) Given time interval , the integration constants; material and iterative controlling parameters; initial values, |
| including , , , , , and their increments. |
| (ii) According to acting loads or time-displacement history, execute iteration within and , to find total |
| displacements by (31) until achieving convergence: |
| (1) For the th nonlinear iteration (not update and for time being in nonlinear iterative loops): |
| Assume , and , then execute the iterative loops and determine by (31): |
| ① Compute the displacement increments , strain increments , , , |
| and the other coefficients. |
| ② Compute plastic parameter , and determine the stress state: If , the stress is |
| located in the plastic area; if , the stress is in the elastic area. |
| ③ Update the stiffness matrix by the following regulations: |
| (a) In the elastic area, eliminate the terms containing in (28). |
| (b) In the plastic area, compute by (13) and (18). |
| ④ Find by (31), calculate , . |
| ⑤ Determine whether or not is less than ; if not, repeat Steps ①④, conduct the th iteration until |
| achieving convergence, then return to Step (2). |
| (2) Update , , and . |
| (3) Re-compute the plastic parameter by the displacements at the final iteration, determine the stress state, and compute |
| the total stresses and inner variable , plastic strains and so on, for the next time step. |
| (iii) Repeat Step (ii), continue the computation of the next load step, determine whether or not failure take places, and obtain |
| the ultimate load. |
