Examples
====




Calculation of the 5 natural modes closest to a given frequency
----


.. code-block:: text

    fashion= CALC_MODES (MATR_RIGI =rigid,
MATR_MASS =mass,

    OPTION =' CENTRE ',
CALC_FREQ =_F (FREQ =100. ,
NMAX_FREQ =5)
);




Calculation of the critical loads contained in a band
----


.. code-block:: text

    mode= CALC_MODES (TYPE_RESU =' MODE_FLAMB ',
MATR_RIGI =rigid,
MATR_RIGI_GEOM =riggeo,

    OPTION =' BANDE ',
CALC_FREQ =_F (

    CHAR_CRIT =( -1.E8,1. 5E8))
);




Chaining INFO_MODE + CALC_MODES (excerpt from SDLS504a)
----


.. code-block:: text

    nbmod1 = INFO_MODE (TYPE_MODE =' MODE_FLAMB ',

    ...

    CHAR_CRIT =( -1.E+6, -5.E+5,0.0,1.E+5,1.1E+6),)


    RESULT0 = CALC_MODES (TYPE_RESU =' MODE_FLAMB ',

    ... ,

    OPTION =' BANDE ',

    CALC_CHAR_CRIT =_F (TABLE_CHAR_CRIT =nbmod1,

    CHAR_CRIT =( -1.E+06,1.E+05)),

    )




Calculation of the natural frequencies contained in the [:ref:`50 ; 150 <50 ; 150>`] Hz band
----

with the inverse power method


.. code-block:: text
mode=CALC_MODES(    MATR_RIGI=rigidite,
MATR_MASS=masse,

    OPTION =' AJUSTE ',
CALC_FREQ =_F (FREQ =( 50.,150.))
))))




Calculation of the natural frequencies closest to 20 and 50 Hz
----

with the inverse power method, with convergence acceleration by the Rayleigh coefficient


.. code-block:: text
mode= CALC_MODES( MATR_RIGI=rigidite,
MATR_MASS=masse,

    OPTION =' PROCHE ',
CALC_FREQ =_F (FREQ =( 50.,150. )),
SOLVEUR_MODAL =_F (OPTION_INV =' RAYLEIGH ')
))))




Dividing into several sub-bands
----

Consider the following sequence:


.. code-block:: text
mode=CALC_MODES(
MATR_RIGI=rigi,

    MATR_MASS =mass,

    OPTION =' BANDE ',
CALC_FREQ =_F (FREQ =( 1.,3.,5.),)
VERI_MODE =_F (),

NORM_MODE =_F (NORME =' TRAN_ROTA ',),

FILTRE_MODE =_F (CRIT_EXTR =' MASS_EFFE_UN '),

IMPRESSION =_F (CUMUL =' OUI ',
CRIT_EXTR =' MASS_EFFE_UN ')
);

We therefore want to search for all the modes included in the global :math:`\mathrm{[}1.,5.\mathrm{]}` Hz band by dividing it into two frequency sub-bands: :math:`\mathrm{[}1.,3.\mathrm{]}` and :math:`\mathrm{[}3.,5.\mathrm{]}`.

Once interpreted, the macro-command consists of the sequence of usual commands described below.


*   Step 1: Determining the number of frequencies in each sub-band


.. code-block:: text

table1= INFO_MODE (MATR_RIGI =rigi,

    MATR_MASS =mass,
FREQ =( 1.,3.,5.))

[:ref:`16 <16>`] _
: nbmodeth

# If the global band is empty: ALARME or ERREUR_FATALE depending on the value of CALC_FREQ/STOP_BANDE_VIDE.


*   Step 2: Calculation and normalization of the modes in each sub-band


.. code-block:: text
[:ref:`17 <17>`]_
et, par défaut, on ne fait pas localement à chaque sous-bande le test de Sturm de post-vérification.

.. code-block:: text

    # If the local sub-band is empty: ALARMEou ERREUR_FATALE according to the value of CALC_FREQ/STOP_BANDE_VIDE.

mode_1= CALC_MODES (MATR_RIGI =rigi,

    MATR_MASS =mass,

    OPTION =' BANDE ',

    CALC_FREQ =_F (FREQ =( 1.3,. ),

    TABLE_FREQ =table1),),
VERI_MODE (STURM =' NON '));
mode_1= NORM_MODE (MODE =mode_1,

    reuse=mode1,
NORME =' TRAN_ROTA ',);
mode_2= CALC_MODES (MATR_RIGI =rigi,

    MATR_MASS =mass,

    OPTION =' BANDE ',

    CALC_FREQ =_F (FREQ =( 3.,5. ),

    TABLE_FREQ =table1),),
VERI_MODE (STURM =' NON '));
mode_2= NORM_MODE (MODE =mode_2,

    reuse=mode2,
NORME =' TRAN_ROTA ',);


    # Verification by a global Sturm test of the correct number of frequencies calculated

    # Determination of the smallest (resp. large) frequency of the first (resp. last) non-empty sub-band: freq_ini (resp. freq_fin).

    # Calculate the number of frequencies in the interval: :math:`\mathrm{[}\text{freq\_ini},\text{freq\_fin}\mathrm{]}`: nbmodeef.

table2= INFO_MODE (MATR_RIGI =rigi,

    MATR_MASS =mass,
FREQ =( freq_ini, freq_end))

# If this number of modes is different from the number of modes originally planned: ERREUR_FATALE.


*   Step 3: Filtering, concatenating, and printing calculated modes.


.. code-block:: text

mode= EXTR_MODE (FILTRE_MODE =_F (MODE =mode_1,
CRIT_EXTR =' MASS_EFFE_UN '),
FILTRE_MODE =_F (MODE =mode_2,
CRIT_EXTR =' MASS_EFFE_UN '),
IMPRESSION =_F (CUMUL =' OUI ',
CRIT_EXTR =' MASS_EFFE_UN '),

    );


.. [1] We just sum up the frequency numbers calculated previously and stored in table1.
.. [2] To avoid redoing the Sturm pretreatment test specific to each sub-band.