5. Miss3D calculation — factor keyword PARAMETRE#
This keyword factor allows you to enter the parameters of the Miss3D calculation: type of interface, foundation, calculation frequencies, spectral and spatial discretization that complete the soil description data.
This data is needed as soon as you need to run Miss3D.
Even if CALC_MISS is used in two stages (calculation then post-processing), the keyword factor PARAMETRE is still necessary because the frequency range of the Miss3D calculation can be used during post-processing. A good practice is to not change the PARAMETRE keyword between these two steps.
The AUTO =” OUI “mode allows you to automatically define the value of certain parameters, in accordance with the advice of the [U2.06.07] and [U2.06.05] documentation. This concerns settings OFFSET_MAX, OFFSET_NB, ALGO,, DREF,, RFIC, and SPEC_MAX..
5.1. Operands FREQ_MIN, FREQ_MAX, FREQ_PAS#
These operands provide the bounds and the frequency step for the Miss3D calculation in frequency resolution (so all cases except when TYPE_RESU =” FICHIER_TEMPS “).
5.2. Operand LIST_FREQ#
This operand provides the list of the real frequencies of the Miss3D calculation. This data is excluded with the keywords FREQ_xxx.
The use of LIST_FREQ is only possible if we do the Miss3D calculation alone or if we are looking for the answer to a harmonic excitation (TYPE_RESU =” HARM_GENE “and the presence of EXCIT_HARMO).
In other cases, it is necessary to provide a list of frequencies at constant steps using the keywords FREQ_MIN, FREQ_MAX, FREQ_PAS.
5.3. Operand FREQ_IMAG#
This operand should only be used in mode TYPE_RESU =” FICHIER_TEMPS “(which corresponds to the LaPlace-Temps method). Indeed, this keyword is used to define the imaginary part of the complex frequency when we place ourselves in the Laplace domain. In all other types of calculation, we are in the frequency domain and the frequency is then always purely real. Only one keyword can be used at a time among FREQ_IMAG, FREQ_MIN, and LIST_FREQ.
5.4. Z0 operand#
This operand gives the dimension of the free surface of the ground.
5.5. Operand SURF#
This operand indicates whether or not we have a superficial foundation.
5.6. Operand ISSF#
This operand indicates whether or not we have a fluid domain and therefore also fluid-structure, soil-fluid and free soil interfaces indicated by the operands GROUP_MA_FLU_STRGROUP_MA_FLU_SOL and GROUP_MA_SOL_SOL in the command.
5.7. Operand RFIC#
This operand indicates the value of the homogeneous parameter at a characteristic distance necessary to eliminate the fictitious resonances.
5.8. Operand ALGO#
This operand indicates for the calculation of impedances whether to use the regularization algorithm for non-superficial foundations or another algorithm for superficial foundations.
5.9. Operand DREF#
This operand indicates the value of the homogeneous parameter at a characteristic distance that makes it possible to eliminate the vertical slope of the impedance for a zero frequency.
5.10. Operand ALLU#
This operand indicates the value of the absorption coefficient between 0 and 1 at the soil-fluid interface. Valid if ISSF =” OUI “.
5.11. Operands OFFSET_MAX, OFFSET_NB#
These operands provide the maximum bound and the spatial discretization breakdown for the calculation of impedances by Miss3D from ground data.
5.12. Operands SPEC_MAX, SPEC_NB#
These operands provide the maximum bound and the division of the spectral discretization for the calculation of impedances by Miss3D from ground data.
If they are not filled in, a spectral discretization will be automatically calculated by Miss3D.
In automatic mode (AUTO =” OUI “), for the case of a homogeneous soil, we know how to calculate the value to be given to SPEC_MAX, according to the formula given in the documentation [U2.06.07].
5.13. Operand TYPE#
This operand makes it possible to store the calculated frequency impedances in a binary format file. If you want to use them with the LIRE_IMPE_MISS [U7.02.32] command, you will then have to make sure to use the same type of file.
5.14. Operand AUTO#
This operand makes it possible to trigger the automatic mode for defining the value of certain Miss3D parameters, in accordance with the advice of the [:ref:`U2.06.07 <U2.06.07>`] and [:ref:`U2.06.05 <U2.06.05>`] documentation. This applies to settings OFFSET_MAX, OFFSET_NB, ALGO,, DREF,, RFIC, and SPEC_MAX. These automatic values are displayed in the message file.
Note that if with this automatic mode, the user still gives the value of all or part of these parameters, these values override the values calculated automatically.
5.15. Operand OPTION_DREF#
This operand allows you to specify, with the mode AUTO =' OUI ', whether to use the DREF option. If yes, then the code automatically calculates the value to be given to it.
5.16. Operand OPTION_RFIC#
This operand allows you to specify, with the mode AUTO =' OUI ', whether to use the RFIC option. If yes, then the code automatically calculates the value to be given to it.
5.17. Operand COEF_OFFSET#
This operand allows you to define the oversampling coefficient for the automatic calculation of the OFFSET_NB parameter (cf.documentations [:ref:`U2.06.05 <U2.06.05>`] and [:ref:`U2.06.07 <U2.06.07>`]). By default it is worth the recommended value of 12 (12 points per element).