3. Operands#
3.1. Operand BASE_MODALE#
♦ BASE_MODALE = Bamo
The name of the mode_meca concept produced by operator DEFI_BASE_MODALE [U4.64.02].
3.2. Operand MACR_ELEM_DYNA#
◊ MACR_ELEM_DYNA = macro_dyna
Name of the dynamic macro-element concept of type macr_elem_dyna identical to the name of the product concept. It is therefore re-entering when it is present. The content of the concept is modified based on the data of the MATR_IMPE * operands present.
3.3. Operand MATR_RIGI#
◊ MATR_RIGI = mr
Name of the concept assembled matrix of the type matr_ass_ DEPL_R or matr_ass_ DEPL_C produced by the operator ASSE_MATRICE [U4.61.22] or the macro command ASSEMBLAGE [U4.61.21] corresponding to the stiffness matrix of the substructure.
3.4. Operand MATR_MASS#
◊ MATR_MASS = mm
Name of the concept matrix assembled of the matr_ass_ DEPL_R type produced by the ASSE_MATRICE [U4.61.22] operator or the ASSEMBLAGE [U4.61.21] macro-command corresponding to the mass matrix.
These two operands should be used if the bamo modal base type “RITZ” is used.
3.5. Operand MATR_AMOR/AMOR_REDUIT#
◊/MATR_AMOR = my
Name of the concept matrix assembled of the matr_asse_ DEPL_R type produced by the operator ASSE_MATRICE [U4.61.22] or the macro command ASSEMBLAGE [U4.61.21] corresponding to the viscous damping matrix, specific to the macroelement. This damping must be of type RAYLEIGH per element (linear combination of stiffness and mass at the level of the element) and is therefore defined by the properties of the material (operator: DEFI_MATERIAU [U4.43.01], operands AMOR_ALPHA and AMOR_BETA).
/AMOR_REDUIT = the
List of reduced damping (percentage of critical damping) corresponding to each vibration mode of the macro-element. The length of the list is (at most) equal to the number of modes specific to the modal base; if it is less, the list is completed with reduced depreciations equal to the last term of the list entered by the user. There is no damping associated with static modes. The generalized damping matrix of the macro-element \(k\) is therefore incomplete diagonally (\(j\) eigenmode index):
\({\overline{\mathrm{C}}}^{k}=\left(\begin{array}{cc}\left({\xi }_{j}\right)& (0)\\ (0)& (0)\end{array}\right)\)
3.6. Operands MATR_IMPE/FREQ_EXTR/AMOR_SOL#
◊ MATR_IMPE = me
Name of the concept matrix assembled of the MATR_ASSE_GENE_C type produced by the operator LIRE_IMPE_MISS [U7.02.32] corresponding to the impedance matrix (of dynamic stiffness strictly speaking) of ground interface \({\mathrm{M}}_{\mathit{imp}}(\mathit{freq})\), constitutive of the macroelement.
♦ FREQ_EXTR = freq
Extraction frequency of the ground interface impedance matrix \(\mathrm{mi}\) \({\mathrm{M}}_{\mathit{imp}}(\mathit{freq})\) required for the calculation of the ground radiative damping matrix from its imaginary part.
◊ AMOR_SOL = amosol
Reduced ground material damping value, equal to half of hysteretic viscoelastic damping \({\xi }_{\mathit{sol}}={\eta }_{\mathit{sol}}/2\), which was used to calculate the \(\mathrm{mi}\) matrix. It is used to distinguish between the specifically material part (viscoelastic) and the radiative part in the damping coming from the ground domain. If it is non-zero, the matrix corresponding to the radiative part \({\mathrm{C}}_{\mathit{imp}}\) is then expressed as:
\(2\pi \mathrm{.}\mathit{freq}\mathrm{.}{\mathrm{C}}_{\mathit{imp}}=\mathrm{\Im }\left({\mathrm{M}}_{\mathit{imp}}(\mathit{freq})\right)-2{\xi }_{\mathit{sol}\mathrm{.}}\mathrm{\Re }\left({\mathrm{M}}_{\mathit{imp}}(\mathit{freq})\right)\)
3.7. Operand MATR_IMPE_INIT#
◊ MATR_IMPE_INIT = mi0
Name of the concept: an assembled matrix of the type Matr_asse_Gene_C, \({\mathrm{M}}_{i0}\), of the same dimension as a mass matrix, produced by the LIRE_IMPE_MISS [U7.02.32] operator corresponding to a ground impedance matrix constituting the macro-element extracted at an almost zero frequency \({\mathrm{M}}_{\mathit{imp}}(0)\). In particular in cases of soil-structure-fluid interaction with the keyword ISSF =” OUI “in the call to LIRE_IMPE_MISS, this makes it possible to extract a mass contribution \(M\) such as, in the low frequency domain:
\({(2\pi \mathrm{.}\mathit{freq})}^{2}\mathrm{.}{\mathrm{M}}_{i0}=\mathrm{\Re }\left({\mathrm{M}}_{\mathit{imp}}(0)\right)-\mathrm{\Re }\left({\mathrm{M}}_{\mathit{imp}}(\mathit{freq})\right)\)
3.8. Operands MATR_IMPE_RIGI/MATR_IMPE_AMOR/MATR_IMPE_MASS#
MATR_IMPE_RIGI=mrMATR_IMPE_AMOR = myMATR_IMPE_MASS = mm
Name of the assembled matrix concepts of the MATR_ASSE_GENE_C type produced by successive calls to the operator LIRE_IMPE_MISS [U7.02.32] in order to extract the respective constitutive contributions of the macro-element in stiffness, damping or mass from a temporal ground impedance matrix. If at least one of the operands is entered, without others being present, then the contributions of these operands to the terms of the macro element will be filled and set to 0.
An example of use is provided by test MISS03B [V1.10.122].
3.9. Operands GROUP_NO/SANS_GROUP_NO#
◊ GROUP_NO = grno
Name of the group of nodes including the list of nodes attached to the degrees of freedom of the interface modes by a LIAISON_INTERF relationship (or LIAISON_SOLIDE if the dynamic interface is reduced to one node) to the nodes of the physical interface of the part of the model on which the dynamic macro element is calculated. Its data is only necessary if this macroelement is used as a supermesh of substructures defined by the keyword AFFE_SOUS_STRUC in a mixed model also including classical finite elements, and in this case, only when the nodes of the physical and dynamic interfaces (the latter defined by DEFI_INTERF_DYNA) do not coincide. For example in the case of the dynamic interface reduced to a node connected by a solid link to the physical interface.
◊ SANS_GROUP_NO = grno
Name of the group of nodes containing the list of nodes of the physical interface of the part of the model on which the dynamic macro element is calculated. These nodes are in direct relationship with the nodes attached to the degrees of freedom of the interface modes by a LIAISON_INTERF relationship (or LIAISON_SOLIDE if the dynamic interface is reduced to one node). Its data is only necessary if this macroelement is used as a supermesh of substructures defined by the keyword AFFE_SOUS_STRUC in a mixed model also including classical finite elements, and in this case, only when the nodes of the physical and dynamic interfaces (the latter defined by DEFI_INTERF_DYNA) do not coincide. For example in the case of the dynamic interface reduced to a node connected by a solid link to the physical interface.
3.10. Keyword CAS_CHARGE#
◊ CAS_CHARGE
This factor keyword makes it possible to define a set of load cases named (keyword NOM_CAS). These load cases serve to apply generalized load vectors applied to the part of the model on which the dynamic macroelement is calculated if then this macro-element is used as a supermesh of substructures in a mixed model also comprising conventional finite elements.
3.10.1. Operand NOM_CAS#
♦ NOM_CAS = nocas
The condensed load under the name nocas (between « quotes ») corresponds to the load defined by the argument VECT_ASSE_GENE or RESU_GENE on the part of the model on which the dynamic macro element is calculated.
3.10.2. Operands VECT_ASSE_GENE/RESU_GENE#
♦ VECT_ASSE_GENE = vgen
The condensed load under the name nocas (between « quotes ») corresponds to the load defined by the alternative arguments VECT_ASSE_GENE or RESU_GENE. It is obtained by the projection either of an assembled load vector, or of a transient result of a second-member force, applied to the part of the model on which the dynamic macro-element is calculated, on the modal basis BAMO defined above. These two options are tested simultaneously in test SDNX101B.
3.11. Operand MODELE_MESURE#
◊ MODELE_MESURE
This factor keyword makes it possible to manually fill in the reduced matrices of the macro-element, using, for example, data from measurements (and imported with LIRE_RESU). At a minimum, we must enter the generalized mass and the natural frequencies. You can also fill in the list of reduced amortizations.
The number of data entered must be equal to the number of modes in the modal base on which the macro element is built.
Methodological point: this type of use of MACR_ELEM_DYNA is justified for the use of the structural modification method based on an experimental model. An overview of the method is given in U2.07.03. The modal base used to build the macro-element should only be composed of the modes specific to the measured structure, and should not include static readings at the interface, because these are false (because they are not measured and, in the current state of knowledge, not measurable).
The sdll137e test case is an example of the implementation of the methodology.
3.11.1. Operand FREQ#
List of identified natural frequencies.
3.11.2. Operand MASS_GENE#
List of generalized masses identified.
3.11.3. Operand AMOR_REDUIT#
List of reduced amortizations identified.