One can impose a priori the history, according to time, of the imposed forces multiplier (FMULT), and/or the imposed displacements multiplier (DMULT).
This is particularly useful for modelisations where the loading speed influences the result (viscous materials, the dynamics, etc.) and where the loading history is no more monotonous.
The multipliers FMULT and DMULT are saved on the file n° 33 (NAMDAT.LIC). The variable IPRES = 8, or IPRES = 18 (combined with NAMDAT.DEP), or IPRES = 28 (combined with NAMDAT.LOA), or IPRES = 38 (combined with NAMDAT.DEP and NAMDAT.LOA), orders the reading of the file (in LAMIN2).
The file n° 33 has a special format. Its structure is described hereafter :
| 1st group (2I5, 1G10.0) | |
|---|---|
| NPAS | Number of definition moments of the imposed values |
| IFOR | = 1 if the format of the group 2.2. is read |
| = 0 if the format by default of the group 2.2. is used | |
| Freq_lic | = 0 for non cyclic values of the imposed multiplier > 0 frequency of the change of multiplier(s) < 0 abs(freq_lic)=period of the change of multiplier |
| if IFOR = 1 (A70) | |
| FORMT | Format of the group 2.2., in parentheses ex. (2I5, G15.0) |
| 2nd groups : NPAS groups of two set of results | |
| 2.1. 1st line of the group (G15.0) | |
| TIME | Definition moment of the multipliers. This moment is compared to the accumulated time, sum of the DELTAT given in the command file. A linear interpolation is realized if a computation step is situated between two definition moments. |
| 2.2. 2nd line of the group (2G10.0 or FORMT) | |
| FMULT | imposed forces multiplier |
| DMULT | imposed displacements multiplier |