Most of the data for this strategy is the same as for the automatic strategy. This page only details the variables that are different from the regular automatic strategy.
This strategy is not valid if one has simultaneously imposed displacements and imposed forces.
Remark: The sphere is a norm of the imposed forces (called by β) and of the displacements. The first step is defined with an imposed load. After the first iteration of the first step, the sphere size is known. From the second iteration, the load is piloted by the sphere size.
| Variable | Values | Description |
|---|---|---|
| IPRES20 | = 0 | When using spherical steps, IPRES must be set to 0 |
| IARCL35 | = 1 | Arc length (1st version) |
| = 2 | Minimum residual displacement method | |
| = 3 | Update plane method | |
| = 4 | Explicit iteration on spheres | |
| = 5 | Arc length (2nd version) |
| Variable | Values | Description |
|---|---|---|
| ISAVE20 | < 0 | compulsory |
| - n | Saving every n step | |
| -9999 | the steps whose number are given in the list of the end of the file are saved (see last line) |
| ISTRA(7)25 | If JSTEP = -1: = NSAMEX - The step amplitude is multiplied by FACMU after NSAMEX “well converged” steps Default value = 2 If JSTEP = -3: = NOPTI - the optimum iteration number per step if JSTEP=-3 (if NOPTI= - 1, the optimum number will be the average of the number of iterations per step) If 2 ≤ IARCL ≤ 5, ISTRA(7)=Nopt. It represents a user-defined desired number of iterations for convergence. Typical values can be 3, 5 or 6 |
| NALPHA45 | Exponent inverse for the computation of FACMU Default value = 3 If 2 ≤ IARCL ≤ 5, NALPHA45 varies between 1 and 4 |
| STRAT(10)30 | DMINMU - Minimum value of the sphere radius Default value DMINMU = 0.01 Rini (Rini computed at the first iteration of the first step) |
| STRAT(11)40 | DMAXMU - Maximum value of the sphere radius Default value DMAXMU = 100 Rini |
| DELTAT10 | Time increment (initial value at start of simulation) |
| FMULT20 | Increment of the imposed or implicit force multiplier (initial value) or value of the sphere radius in case of restarting the simulation from a previous set of results |
| DMULT30 | Increment of the imposed displacements multiplier (initial value) or value of the sphere radius in case of restarting the simulation from a previous set of results |
| PRECU40 | Precision for convergence on displacements increments |
| PRECF50 | β0 = parameter to compute β = 1 by default |
One blank line
| ??NOPAS?? | ??List of the steps numbers for which one wishes to save results (If ISAVE=-9999)?? |
| ALSAV | Multiplier of the imposed forces or displacements for which one wishes a printing according to IOPT and a saving on NRESU (ISAVE <> -9999) |