3. Operands#
3.1. Keyword MODELE_CALCUL#
♦ MODELE_CALCUL
Keyword factor bringing together all the keywords relating to the expansion base, generally obtained by calculation (hence the name).
3.1.1. Keyword MODELE#
♦ MODELE = model number
modele_sdaster designating the model on which we will extend the measurement
3.1.2. Keyword BASE#
♦ BASE = base
mode_meca serving as the basis for expansion.
The base must not have collinear vectors, and the number of modes used must be less than the number of DDL measures (preferably, nmodes << nmes) otherwise, the system to be solved is under-determined, which can lead to a fatal error, and a code outage.
3.1.3. Keyword NUME_ORDRE/NUME_MODE#
List the order numbers or modal positions of the modes you want to use for expansion.
3.2. Keyword MODELE_MESURE#
♦ MODELE_MESURE
Keyword factor bringing together all the keywords relating to the experimental base that one wishes to extend
3.2.1. Keyword MODELE#
♦ MODELE = modelexp
modele_sdaster designating the model associated with the experimental mesh. Knowledge of the nodes is generally sufficient to determine an experimental mesh. The associated model can then be defined in the following way:
MODELEXP = AFFE_MODELE (MAILLAGE = MAIEXP,
AFFE = _F (GROUP_MA = “CAPTEURS”,
PHENOMENE = “MECANIQUE”,
MODELISATION = “DIS_T”,),);
CAREXP = AFFE_CARA_ELEM (MODELE = MODELEXP,
DISCRET = _F (GROUP_MA = “CAPTEURS”,
REPERE = “GLOBAL”,
CARA = “K_T_D_N”,
VALE = (100.0,100.0,100.0,),
),);
The value of the stiffness given is arbitrary, it is not used in the calculation.
NB: to use the PROJ_CHAMP operator in the macro, you need to generate a nume_ddl associated with this mesh. To do this, it is also necessary to assign a material to the model, calculate the elementary matrices (stiffness for example) and create the numbering with NUME_DDL.
3.2.2. Keyword MESURE#
♦ MESURE = my
dyna_harmo or*mode_meca* to be extended. This data is generally imported from a measurement result (.unv file) with the LIRE_RESU operator.
3.2.3. Keyword NUME_ORDRE/NUME_MODE#
List of integers. Allows you to select the modes you want to extend.
3.2.4. Keyword NOM_CHAM#
♦ NOM_CHAM = “DEPL”…
Experimental magnitude to be extended.
3.3. Keyword RESOLUTION#
Two resolution techniques are proposed for the opposite problem: SVD truncated, LU method.
For SVD, you can choose to truncate the smallest singular values to improve the conditioning of the problem (choice of “eps”), or use Tikhonov-type regularization.
We can refer to the documents [U4.73.01] (doc from PROJ_MESU_MODAL) and [R6.03.01] (reference doc on the decomposition into singular values).
3.4. Keyword NUME_DDL#
Allows you to impose the numbering to be used for the PROJ_CHAMP operator. For more details, refer to the documentation in PROJ_CHAMP [U4.72.05].