4. Model definition#

4.1. Keyword TYPE_RESU#

Defines the type of analysis to be performed. Five values are allowed:

  • FICHIER: only the execution of Miss3D is done. The files produced by Miss3D are directly retrieved from the files identified by the logical units UNITE_RESU_IMPE and UNITE_RESU_FORC. CALC_MISS does not return a concept (nothing to the left of the « = » sign).

  • FICHIER_TEMPS: only the execution of Miss3D is done. The files produced by Miss3D are directly retrieved from the files identified by the logical units UNITE_RESU_RIGI, UNITE_RESU_MASS, UNITE_RESU_AMOR and UNITE_RESU_FORC from the files identified by the logical units,, and. CALC_MISS does not return a concept (nothing to the left of the « = » sign). This corresponds to the Laplace-Temps method.

  • CHARGE: a mechanical load is calculated from the seismic force file.

  • HARM_GENE: we calculate the harmonic response of the structure (such as harm_gene) after running Miss3D or from files from a previous resolution.

  • TRAN_GENE: we calculate the temporal response of the structure (tran_gene type) after running Miss3D or from files from a previous resolution.

  • TABLE: we calculate the harmonic response of the structure to a unit load at certain points, and we return a table-type concept that contains the functions of responses in displacement, speed, acceleration and oscillator spectrum recombined on the load cases.

  • TABLE_CONTROL: we get the transfer functions at certain control points and the harmonic and temporal responses to a given acceleration from the Miss3D calculation. A table-like concept is produced.

4.2. Operands PROJET/REPERTOIRE#

The REPERTOIRE keyword allows you to define a directory (entered by its full path on the execution machine) where the Miss3D calculation will be executed. You can find all Miss3D data and result files there (for debugging for example). These files will start with a radical name given by the operand PROJET (which is MODELE by default).

If REPERTOIRE is not defined, the execution will take place in a temporary directory that will be destroyed at the end of the calculation.

4.3. Operand MACR_ELEM_DYNA#

It is the dynamic macroelement of the structure (macr_elem_dyna type) produced by the command of the same name (cf. [U4.65.01]). If this one is not entered, it will be automatically calculated by CALC_MISS from the modal base and the matrices provided.

4.4. Operand BASE_MODALE#

Basis of the modes of the structure. If MACR_ELEM_DYNA is not entered, this modal base is used to determine it.

When we only perform the Miss3D calculation (TYPE_RESU =” FICHIER “), we provide either MACR_ELEM_DYNA or BASE_MODALE.

When requesting post-processing, it is necessary to enter the keyword BASE_MODALE (used for harmonic calculation). However, it is possible to provide a specific macro-element in case of need.

4.5. Operands MATR_RIGI and MATR_MASS#

These keywords make it possible to provide the stiffness and mass matrices of the structure.

They will be used during the harmonic calculation and, if necessary, to create the dynamic macro element.

4.6. Operand MATR_AMOR#

This keyword makes it possible to provide a damping matrix for the structure used during the harmonic calculation alternately with the use of modal damping with the keyword AMOR_REDUIT.

4.7. Operand UNITE_IMPR_ASTER#

Logical unit number on which you can retrieve the file produced by the operator IMPR_MACR_ELEM format “MISS_3D” called internally by CALC_MISS. The value by default is 25.

4.8. Operands UNITE_RESU_IMPE, UNITE_RESU_RIGI, UNITE_RESU_MASS, UNITE_RESU_AMOR, UNITE_RESU_FORC#

Logical unit numbers of files containing ground impedances (or its breakdown into stiffness, mass, and damping) and seismic forces by frequency.

If you only ask for the Miss3D calculation, UNITE_RESU_IMPE, UNITE_RESU_RIGI,,,, UNITE_RESU_MASS, UNITE_RESU_AMOR and UNITE_RESU_FORC are used depending on the case to store the result files.

If post-processing is requested, these arguments should only be used if the Miss3D calculation has been executed before (the files are then data for CALC_MISS).

The operands UNITE_RESU_RIGI, UNITE_RESU_MASS, UNITE_RESU_AMOR are for use specific to the Laplace-temps method (case TYPE_RESU = “FICHIER_TEMPS”) and the presence of UNITE_RESU_AMOR or UNITE_RESU_MASS makes the keyword factor MATR_GENE mandatory.

Note

In the Miss3D execution, the post-processing of impedances (respectively seismic forces) is only performed if the keyword UNITE_RESU_IMPE (respectly UNITE_RESU_FORC) is filled in. This makes it possible to reduce the calculation time a little bit.

4.9. Operand GROUP_MA_INTERF#

This keyword is used to define the list of surface mesh groups constituting the soil-structure interface (transmitted internally to the operator IMPR_MACR_ELEM [U7.04.33]).

4.10. Operands GROUP_MA_FLU_STR/GROUP_MA_FLU_SOL/GROUP_MA_SOL_SOL#

In the case of a soil-fluid-structure interaction, these keywords make it possible to complete the list of surface mesh groups consisting respectively of the fluid-structure, fluid-ground and free soil interfaces (transmitted internally to the operator IMPR_MACR_ELEM [U7.04.33]).

The keyword GROUP_MA_SOL_SOL for the free soil interface can also be optionally present in soil-structure interaction, in order to model the imperfect connections between the soil and the structure along the sinking of the foundation.

4.11. Operand TABLE_SOL#

The soil stratification description data is provided in the form of a table produced by the DEFI_SOL_MISS command (cf. [U7.02.34]).

4.12. Operand MATER_SOL#

For a homogeneous soil, the properties of the soil are provided: E is the Young’s modulus, NU the Poisson’s ratio, RHO the density.

4.13. Operand MATER_FLUIDE#

In the case of a soil-fluid-structure interaction analysis (ISSF =” OUI “under PARAMETRE), the properties of the fluid are provided: RHO is the density, CELE the speed of the waves, AMOR_BETA the damping.

It is also indicated whether the domain represents a fluid half-space or not according to the definition of Miss3D.

4.14. Operand VERSION#

The name of the Miss3D release. The value by default corresponds to the version of Miss3D in operation.

4.15. Operand SOURCE_SOL#

Keyword factor defining the loads from point sources in the ground domain, given by their direction and source coordinates. Only if TYPE_RESU =” FICHIER “

Vector DIRECTION is automatically normalized to 1 by Miss3D.

4.16. Operand SOURCE_FLUIDE#

Keyword factor defining the loads coming from point sources of pressure in the fluid domain, given by the coordinates of the source. Only if TYPE_RESU =” FICHIER “

4.17. Operand AMOR_REDUIT#

List of reduced depreciation (sent internally to DYNA_LINE_HARM [U4.53.11]).

Let \(\mathit{nbmode}\) be the number of dynamic modes defined in the modal base, and \(\mathit{nbamor}\) the number of reduced amortizations provided.

If \(\mathit{nbamor}<\mathit{nbmode}\), then we complete the list of depreciations up to \(\mathit{nbmode}\) with the last depreciation in the list.

Zero damping is then added which will be applied to the static modes present.

4.18. Operand PRECISION#

Precision parameter of the LaPlace-Temps calculation method (case TYPE_RESU = “FICHIER_TEMPS”). It is strongly recommended to leave the value by default.

4.19. Operand COEF_SURECH#

Parameter to impose the oversampling coefficient for the LaPlaceTemps method. It is recommended to keep the value by default in order to guarantee a good result over the entire calculation window. In fact, when this operand is equal to 1.0 (no oversampling step), the transient impedance is valid only over about 70% of the calculation window. Thus, if the user increases this coefficient, the calculation precision will be improved, but with an additional calculation cost that is proportional to this value.

4.20. Operand FACTEUR_INTERPOL#

Parameter of the LaPlace-Temps calculation method (case TYPE_RESU = “FICHIER_TEMPS”). It gives the value of the interpolation step and therefore of the factor for reducing the calculation time.

4.21. Operand PCENT_FREQ_CALCUL#

Parameter of the Laplace-Temps calculation method. It gives as a percentage the ratio between the number of samples without interpolating and the total number of samples.

4.22. Operand COEF_MULT#

Parameter of the Laplace-Temps calculation method. It makes it possible to assign a multiplying factor to the temporal impedances. Useful for example for conversions to 2D models by dividing the results of 3D impedances by domain thickness.

4.23. Operand TYPE_FICHIER_TEMPS#

Parameter of the LaPlace-Temps calculation method (case TYPE_RESU = “FICHIER_TEMPS”) which allows you to specify the format of the output time file, between “ASCII” (default) and “BINAIRE”. The binary format saves space and a little time but is not readable by the user. The format thus defined must be consistent with the format specified with the TYPE keyword under the FORCE_SOL option in AFFE_CHAR_MECA.

4.24. Operands INST_FIN, PAS_INST, and INST_ECRI_FIN#

The keywords PAS_INST and INST_FIN are mandatory with the LaPlaceTemps calculation method (case TYPE_RESU = “FICHIER_TEMPS”) to give the time step and the final instant of the method integration calculation.

The INST_ECRI_FINfacultatifpermet keyword is to limit the storage size of temporal impedances sufficient for the calculation of seismic forces. Otherwise, this size is determined from INST_FIN.

4.25. Operand MATR_GENE#

This optional factor keyword is used for the LaPlaceTemps method, so for TYPE_RESU = “FICHIER_TEMPS”. It allows you to specify all the options relating to impedance calculations ((cf. test case MISS03 and its associated documentation [V1.10.122]). If this optional factor keyword is used, then you must also define the values of the UNITE_RESU_AMOR and UNITE_RESU_MASS operands.

4.25.1. Operand DECOMP_IMPE#

This keyword allows you to specify the impedance decomposition method. It is recommended to leave the value by default (“PRODUIT”).

4.25.2. Operand AMOR_HYST#

This keyword makes it possible to specify how hysteretic damping in the ground will be taken into account.

This keyword allows you to specify the impedance decomposition method. It is recommended to leave the value by default (“PRODUIT”). There are two possible choices:

  • “DANS_MATR_AMOR”: the damping matrix given by the user (via MATR_AMOR under MATR_GENE) takes into account the hysteretic damping of the ground.

  • “DANS_IMPEDANCE”: this is the opposite case of the previous one.

4.25.3. Operands MATR_MASS, MATR_RIGI, and MATR_AMOR#

These arguments are used to define mass, stiffness, and damping matrices that can be used by impedance decomposition.

If you have AMOR_HYST = “DANS_MATR_AMOR”, then you must enter, at least, MATR_AMOR.

Conversely, AMOR_HYST = “DANS_IMPEDANCE”, so it is sufficient, at least, to give one of the three matrices for the decomposition.

This keyword makes it possible to specify how hysteretic damping in the ground will be taken into account.

This keyword allows you to specify the impedance decomposition method. It is recommended to leave the value by default (“PRODUIT”). There are two possible choices:

  • “DANS_MATR_AMOR”: the damping matrix given by the user (via MATR_AMOR under MATR_GENE) takes into account the hysteretic damping of the ground.

  • “DANS_IMPEDANCE”: this is the opposite case of the previous one.

4.26. Operand EXCIT_SOL#

This optional keyword factor is used to characterize the excitation transmitted by the ground: definition of seismic forces. If you only want to calculate impedances, this keyword is useless.

4.26.1. Operand UNITE_RESU_FORC#

Allows you to define the logical unit of the generated file that will contain the seismic forces, which will be reusable in DYNA_NON_LINE via a loading type EXCIT_SOL in AFFE_CHAR_MECA (cf. test case MISS03C and its associated documentation [V1.10.122]).

4.26.2. Operands NOM_CHAM, CHAM_X, CHAM_Y, and CHAM_Z#

These arguments are used to specify the input signal. Its nature (moving signal, speed or acceleration) is indicated by the value of NOM_CHAM. By default we expect an imposed move.

This signal can have from one to three components, following \(X\), \(Y\) and \(Z\) and for each direction, we can give the corresponding function: CHAM_X, CHAM_Y and CHAM_Z.