Operands ========= Operands MODELE/CARA_ELEM ---------------------------- .. code-block:: text ♦ MODELE = model, ◊ CARA_ELEM = caraelem, These keywords are used to provide information on: * the name of the model (model) whose elements are the subject of mechanical calculation. * the name of the characteristics of the structural elements (plates, beams, discretes,...) if they are used in the model. .. _Toc394671249: Keyword factor MATER_ELAS -------------------------- .. code-block:: text ◊ MATER_ELAS = _F ( ♦/MATER = matt /♦ E = e ♦ AMOR_HYST = amorhyst ♦ RHO = rho ♦ NU = naked ♦ GROUP_MA = GMA ) This keyword makes it possible to assign an elastic material **without frequency dependency** to elements belonging to GROUP_MA. The material can be defined before the macro-order using the operator DEFI_MATERIAU [:external:ref:`U4.43.01 `]; in this case, this material is recalled with the keyword MATER. The material can also be defined here by its properties: Young's modulus E, density RHO, Poisson's ratio NU, and hysteretic damping AMOR_HYST. This keyword factor can be repeated as many times as there are elastic materials **with no frequency dependence** in the structure. .. _Toc394671250: Keyword factor MATER_ELAS_FO ----------------------------- .. code-block:: text ♦ MATER_ELAS_FO = _F ( ♦ E = l_e ♦ AMOR_HYST = l_love ♦ RHO = rho ♦ NU = naked ♦ GROUP_MA = GMA ) This keyword makes it possible to assign a viscoelastic material **with** **frequency dependence** to elements belonging to GROUP_MA. The mechanical properties of viscoelastic material are of two types: * those that depend on frequency: Young's modulus E and damping factor AMOR_HYST; they are provided by functions indexed by frequency, produced by DEFI_FONCTION/NOM_PARA =' FREQ '[:external:ref:`U4.31.02 `]); * those that are constant: density RHO and Poisson's ratio NU. This keyword factor can be repeated as many times as there are visocelastic materials with **frequency dependence** in the structure. .. _Toc394671256: Keyword TYPE_RESU ----------------- .. code-block:: text ◊ TYPE_RESU =/'HARM' [DEFAUT] /'MODE' This keyword is used to define the type of calculation to be performed: * the choice 'MODE' makes it possible to calculate the natural modes of the structure; * the calculation 'HARM', makes it possible to obtain the frequency response of the structure to a given excitation; it is also possible to recover the natural modes calculated using the keyword MODE_MECA. .. _Toc394671255: Keywords FREQ/LIST_FREQ -------------------------- .. code-block:: text ♦/FREQ = l_f /LIST_FREQ = lfreq In the case of a modal calculation of the structure (TYPE_RESU =' MODE '), this keyword makes it possible to define the frequency band for searching for the modes. The list must then contain exactly 2 values (strictly increasing). In the case of a harmonic calculation of the structure (TYPE_RESU =' HARM '), this keyword makes it possible to define the discrete frequencies for which the structure response is calculated. The list must then contain at least 2 strictly increasing values. .. _Toc394671260: Keywords TYPE_MODE/RESI_RELA ------------------------------ .. code-block:: text ◊ TYPE_MODE =/'REEL' [DEFAUT] /'BETA' /'COMPLEXE' Several choices for calculating natural modes are possible: real modes, beta-modes (which are improved real modes giving better precision of the results, cf. [:ref:`R5.05.09 `]), as well as complex modes. The calculation of complex modes makes it possible to obtain modal depreciations. However, this type of mode cannot be used to carry out a harmonic calculation (TYPE_RESU =' HARM '). Note: If you calculate complex modes, you can get the modal depreciations in a Python list with this function: liste_python=modes. LIST_PARA () ['AMOR_REDUIT'] (this requires using PAR_LOT =' NON 'in the DEBUT command). .. code-block:: text ◊ RESI_RELA =/1.E-3 [DEFAUT] /eps The calculation of natural modes with the iterative method has a convergence criterion called RESI_RELA. An eigenmode is retained in the modal base when the relative difference between the natural frequencies calculated between two successive iterations is less than RESI_RELA. .. _Toc394671257: Keyword factor EXCIT --------------------- .. code-block:: text ♦ EXCIT =_F ( ♦ CHARGE = load ) This keyword allows the assignment of loads (boundary conditions, excitation forces,...) that were previously defined by the operator AFFE_CHAR_MECA [:external:ref:`U4.44.01 `]. **Note:** *Currently, for external excitations, only excitations of type* FORCE_NODALE *are compatible with the command* DYNA_VISCO *.* *For harmonic calculation, the natural mode base is enriched, in a manner that is transparent to the user, by the static modes associated with the excited nodes.* .. _Toc394671258: Keyword NOM_CHAM (if TYPE_RESU =' HARM ') -------------------------------------- .. code-block:: text ◊ NOM_CHAM =/'DEPL' [DEFAUT] /'VITE' /'ACCE' This keyword allows you to define which fields will be saved in the result concept (movement, speed or acceleration). It is possible to save several fields by giving a list, for example NOM_CHAM =( 'DEPL', 'ACCE'). .. _Toc394671259: Keyword MODE_MECA (if TYPE_RESU =' HARM ') ------------------------ ◊ MODE_MECA = CO ('modes') If this keyword is present, two concepts will be produced by the macro command: * the modes_meca concept * the visco concept like dyna_harmo For example, the concept modes can be printed classically with the IMPR_RESU [:external:ref:`U4.91.01 `] command. .. _Toc3946712591: Keyword COEF_FREQ_MAX (if TYPE_RESU =' HARM ') ------------------------------------------- ◊ COEF_FREQ_MAX = cfmax [R] During a harmonic calculation, the multiplier coefficient COEF_FREQ_MAX makes it possible to obtain more accurate frequency response values, by multiplying by COEF_FREQ_MAX the value of the maximum calculation frequency of the modal projection base. The minimum value for this parameter is 1.5. .. _Toc394671263: Keyword INFO ------------ .. code-block:: text ◊ INFO =/1 [DEFAUT] /2 Indicates the print level in file MESSAGE.