Solution dialog box (Simcenter Samcef Linear Harmonic Response Analysis)

Solution Method

Modal Superposition (.DGE IRDY)

Determines whether you solve with modal superposition or direct integration.If you select this check box, the software uses modal superposition to solve an approximation of the problem. The modal solver computes the number of modes you set in Number Of Eigenvalues. Solving with modal superposition is faster than solving with direct integration, but the results are limited by the modal basis of the number of modes you set to compute. The higher the number of modes that are computed, the more accurate the results are. If you clear this check box, the software uses direct integration to solve the full problem. The results are more accurate, but the solve requires more computation time.

General page

Foreground Run
Run Job in Foreground	Runs the Simcenter Samcef job in the foreground.
User-Defined Text
Prolog****Epilog	Specifies the User Defined Text to prepend (Prolog) or append (Epilog) to the solver input file. For more information, see Customizing a Simcenter Samcef input file with user defined text.
Boundary Condition Control Variables
Evaluation Time	If your boundary conditions use time-dependent fields, you can define the time at which the field will be evaluated.The same time value is used for all the time-dependent fields.This time value is also used for the Mechanical Loads Summary command. For more information, see Computing mechanical loads.
Temperature
Default Reference Temperature (.GEL TEMP)	Specifies the reference temperature used to compute thermal strains. For more information, see Reference and Initial Temperatures in Samcef (Simcenter Samcef).

Frequency page

Frequency Discretization
Frequency Discretization	Specifies the Frequency Discretization modeling object.To edit an existing frequency discretization modeling object, select it from the list and click Edit. To create a new one, click, Create Modeling Object .For more information, see Linear harmonic response solution options (Simcenter Samcef).
Additional Frequency Definition units	Specifies the units of the frequencies that you can add in addition to the Frequency Discretization modeling object.
Additional Frequency Definition list	Lets you paste or type frequencies that are not included in the Frequency Discretization modeling object. You can type a comma-delimited set of frequencies, or you can press Enter after each frequency.The Frequency Discretization modeling object specifies frequencies in a linear progression, that is, by a specified number of steps within a given range. If you want to add specific frequencies that are not covered by the steps within that range, you can add those frequencies manually. For example, if the Frequency Discretization modeling object specifies a range of 1,000 Hz through 10,000 Hz with Number of Frequency Steps set to 100, frequencies 1,000 Hz, 1,100 Hz, 1,200 Hz, and so on are included. If you are interested in 1,050 Hz, 1,060 Hz, and 1,070 Hz, you can enter those values here. The additional frequencies are exported as .CAT FREQ.To manage the frequencies, you can use the Cut , Copy , and Paste commands.

Modal Parameters page

Modes Selection
Available when the Modal Superposition (.DGE IRDY) check box is selected.
Number Of Eigenvalues	Sets the number of modes to compute. To view these results, select the Generate Result Files for Modal Analysis check box and then import the modal results (*dy.des) in the Post Processing Navigator.
Lower Frequency	Lets you set the lowest frequency of the modes to compute.
V1	Appears when the Lower Frequency check box is selected.Sets the lowest frequency of the modes to compute.For more information, see the V1 parameter of the Samcef .ALGO command.
Upper Frequency	Lets you set the highest frequency of the modes to compute.
V2	Appears when the Upper Frequency check box is selected.Sets the highest frequency of the modes to compute.For more information, see the V2 parameter of the Samcef .ALGO command.
Effective Masses
Available when the Modal Superposition (.DGE IRDY) is selected.
Effective Masses Options	Enables the effective masses computation. This option and the Calculation of the Modal Participation Factors Options and Calculation of the Modal Reactions options help you to measure solution errors when the solver establishes a truncation method (frequency cutoff) to solve very stiff structures where behavior at high frequency is dominant.
Option	Appears when the Effective Masses Options check box is selected.Specifies the effective masses computation option. Calculation of the Effective Modal MassesComputes and prints the effective modal massesCalculation of the Effective Modal Masses and Distances to Structural AxesComputes and prints the effective modal masses and their positions in the absolute (global) structural coordinate system.No Calculation of the Effective Modal MassesPrevents the computation of modal masses.For more information, see the MEFIMP parameter of the Samcef .ALGO command.Note: Effective modal masses values, their positions, the modal participation factors, and the modal reactions are printed only in the Simcenter Samcef .res output file. They are not available in post-processing.For more information about the Effective Masses Options, see the Simcenter Samcef modal analysis manual.
The following check boxes appear when the Effective Masses Option check box is selected, and Option is set to Calculation of the Effective Modal Masses or Calculation of the Effective Modal Masses and Distances to Structural Axes.
Calculation of the Modal Participation Factors Options	Computes and prints the participation factors.For more information, see the PARTIMP parameter of the Samcef .ALGO command.
Calculation of the Modal Reactions	Computes and prints the modal reactions.For more information, see the REAIMP parameter of the Samcef .ALGO command.
Curvature for shells and beams
Compute Curvature for Mindlin Shells and Beams (.ALGO MINO)	Specifies that the curvatures for Mindlin elements are automatically computed by the solver. For more information, see the MINO parameter of the Samcef .ALGO command.
Threshold Angle (.ALGO SNORM)	Appears when the Compute Curvature for Mindlin Shells and Beams (.ALGO MINO) check box is selected.Sets the angle value above which the mean normals are not computed.For more information, see the SNORM parameter of the Samcef .ALGO command.
Cyclic Symmetry
Activate Cyclic Symmetry	Specifies that the model contains cyclic symmetry conditions.
Wave Number	Appears when the Activate Cyclic Symmetry check box is selected.Sets the wave number to compute.For information on the wave number, see Wave number in cyclic symmetry solutions (Simcenter Samcef).

Solver Parameters page

Calculation of Residuals
Appears when the Modal Superposition (.DGE IRDY) is selected.
Calculation of Residuals (.DGE IRDY)	Appears when the Modal Superposition (.DGE IRDY) check box is selected.Provides print outs of the reactions at the locations where the structure is clamped or partially constrained.For more information, see the IRDY parameter of the Samcef .DGE command.
Solver Type
Solver (.SAM MF)	Specifies the solver type.SparseRecommended for a linear solution.FrontalReserved for a very few specific cases that are described in the Simcenter Samcef documentation.For more information, see the MF parameter of the Simcenter Samcef .SAM command.
Advanced
Equations Reordering Method (.ALGO MMFOPT)	Appears when Solver (.SAM MF) is set to Sparse.Specifies the equations reordering method. AutomaticAllows Simcenter Samcef to choose the best method during the solve.METISFor more information, see Solution methods in the Simcenter Samcef documentation.MMDFor more information, see Solution methods in the Simcenter Samcef documentation.For more information, see the MMFOPT parameter of the Simcenter Samcef .ALGO command.
Damping
For information on superposing structural and modal damping, see Superpose damping in a dynamic response analysis.
Ignore Damping Matrix from Modal Solution (.DGE IUAM)	Ignores the element damping matrices that the modal analysis computes. This is useful when you define damping for some elements, but after those damping matrices are computed, you want to impose new modal damping. To do this, set damping at the solution level by editing the solution and selecting the Modal Damping check box on the Solver Parameters page. This requires that you are using modal superposition (the Modal Superposition check box is selected).Note: This option has no effect on modal damping for the linear harmonic response solution because in this case, only the diagonal terms of the damping matrix are taken into account.For more information, see the IUAM parameter of the Simcenter Samcef .DGE command.
Rayleigh Damping	Lets you set stiffness and mass coefficients.
Stiffness Coefficient (.DGR ALAM)	Appears when the Rayleigh Damping check box is selected.Sets the stiffness coefficient for Rayleigh damping.
Mass Coefficient (.DGR DLAM)	Appears when the Rayleigh Damping check box is selected.Sets the mass coefficient for Rayleigh damping.
Modal Damping	Appears when the Modal Superposition (.DGE IRDY) check box is selected.Lets you define the relative damping per modes by selecting a field and setting a scale factor for the damping.
Specify Field	Appears when the Modal Damping check box is selected.Defines a field or table field that lets you set specify mode numbers (independent domain) and a critical damping rate (dependent domain).The critical damping rate (multiplied by the scale factor) must be between 0 and 1.
Scale Factor	Appears when the Modal Damping check box is selected.Sets a scale factor to increase or decrease the critical damping rate.
Reactions
Appears when the Modal Superposition (.DGE IRDY) is selected.
Enable Quasi-Static Correction (.DGE NLC)	Enables quasi-static correction in the modal response. This correction artificially adds vibration modes for the solver to take into account. Each time you select modal superposition, the truncation of the set of eigenmodes introduces an error in the spatial representation of the load. However, this error can be compensated for with the quasi-static correction. The quasi-static correction guarantees a statically accurate solution, with the only approximation being the representation of inertia forces and dissipation. It corresponds to adding one static vector in the modal basis.Adding the vibration modes is useful in these circumstances:When the modes might otherwise be ignored due to the modal base projection.When the modes are required due to forces that excite a degree of freedom, that is, the correction is important for reaction and stress computation.For more information, see the NLC parameter of the Samcef .DGE command.

Storage page

The storage frequency values that you set in the Frequency Discretization modeling object override these global values only during the computation frequency that you set in the current Frequency Discretization modeling object.

Storage Frequency
Storage Frequency of all Nodal Results (.DGE IA16)	Sets the storage frequency for nodal results.For more information, see the IA16 parameter of the Samcef .DGE command.
Storage Frequency of all Element Results (.DGE IA4)	Sets the storage frequency for element results.For more information, see the IA4 parameter of the Samcef .DGE command.
Storage Frequency of XY Results (.DGE IA19)	Sets the storage frequency for XY graph results.For more information, see the IA19 parameter of the Samcef .DGE command.

Output page

Output Requests
Select an existing one from the list or click Create Modeling Object to create a new output request.Click Edit to edit the selected output request.
Output Requests	Specifies structural output requests. For more information, see Samcef output requests.
Nodal Time History Output	Specifies output requests from specified nodes. For more information, see Time history graphs: nodal results (Simcenter Samcef linear harmonic).
Element Time History Output	Specifies output requests from specified elements. For more information, see Time history graphs: element results (Simcenter Samcef linear transient or linear harmonic).
Advanced
Appears when the Modal Superposition (.DGE IRDY) check box is selected.
Generate Result Files for Modal Analysis	Generates additional result files (*dy.des, *dy.fac, and .sdb) in the modal analysis.

Integration Scheme page

Appears when the Modal Superposition (.DGE IRDY) check box is cleared.

Integration Scheme
Scheme	Specifies the integration scheme. NewmarkAcceptable for most applications.Hilber-Hughes-TaylorRecommended if numerical damping is required.
Newmark First Parameter (.DGR BETA)	Appears when Scheme is set to Newmark.Specifies the first value of the Newmark formula. For more information, see the BETA parameter of the Samcef .DGR command.
Newmark Second Parameter (.DGR GAMA)	Appears when Scheme is set to Newmark.Specifies the second value of the Newmark formula. For more information, see the GAMA parameter of the Samcef .DGR command.
Hilber-Hughes-Taylor Parameter (.DGR ALFA)	Appears when Scheme is set to Hilbert-Hugues-Taylor Parameter (.DGR ALFA).Specifies the value for the Hilber-Hughes-Taylor formula. For more information, see the ALFA parameter of the Samcef .DGR command.

Chaining page

Activate Chaining	Activates chaining. For more information, see Chaining solutions (Simcenter Samcef).

User page

User Parameters
User Parameters for .ALGO	Lets you specify user parameters for the .ALGO Samcef command.
User Parameters for .SAM	Lets you specify user parameters for the .SAM Samcef command.
User Parameters for .GEL	Lets you specify user parameters for the .GEL Samcef command.
User Parameters for .DGE	Lets you specify user parameters for the .DGE Samcef command.

Note:

The added texts must be compliant with the Samcef Command Language terminology. For more information, see the Simcenter Samcef documentation.

How do I

Chain a nonlinear analysis with a dynamic response analysis (Simcenter Samcef)

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Linear harmonic response solution options (Simcenter Samcef)

Dynamic response analysis workflow (Simcenter Samcef)

Damping (Simcenter Samcef)

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Solution dialog box (Simcenter Samcef Linear Harmonic Response Analysis), Simcenter 3D 2021.1 Series

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