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Analysis with supernodes on the highest level is not possible

Version: All

Running an analysis for a model including piles results in the following error indicated in Sestra.lis:

*** INPUT ERROR ***                                                                                                               
Analysis with supernodes on the highest level is not possible.

unless saving is specified.

The procedure to solve this issue is outlined in the attached FAQ document.

Please see the attached document 00003655 Supernode error.

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Version: All

If you are having larger differences in between summed loads and reaction forces, run analysis using 2nd order elements.

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DOFs fixed in Presel will not print out reaction forces

Version: All

If a DOF is defined originally as super and changed into fixed inside Presel, the corresponding reaction force will not be printed out by Sestra in the .lis file or in the results files. Therefore, results presentation in GeniE or Xtract will not print reaction forces for this DOF. This force can be computed from the shear forces in the beam. Alternatively, defining this DOF as fixed originally will provide the reaction forces.

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Version: All

If you are using Rigid support link in the model for dynamic analysis then it may end up with an error. It may work in Superlement technique in a way that beam end node (master node) has to be represented as super node.

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Ensure GeniE generates correct Sestra input file

This is applicable when a user cant use the Automatic generation of input files due to some of the cards not being supported via GeniE GUI or analysis type not supported directly in GeniE. Users can uncheck Automatic generation of input files at any Edit Analysis dialog box (i.e. Linear Analysis). To ensure that all input cards required from GUI are updated in Sestra.inp file when clicking Generate input files, the user needs to follow the below steps:

  1. select the required solver (or any other input)
  2. click "Apply"
  3. click "Generate Input files"
  4. click "OK" to close the dialog box The generated input file may then be edited and will not be overwritten as long as Automatic generation of input files remains unchecked. The contents of Sestra.inp is further described in the Sestra user manual.

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Hinges with 2nd order elements

Version: All

End moments will not be zero if you use hinge properties for 2nd order elements.

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How to avoid basic errors in tension/compression analysis.

Version: Since 8.5-01

  1. Make sure all tension/compression concept elements are not divided into many FEM elements. 1 concept tension/compression beam should only consist of 1 FEM beam element. Expected error: TensionCompressionDriver.log will display: No truss elements have been assigned the Tension only or the Compression only beam type property - no analysis has been run.
  2. Don't use 2nd order elements for analysis. Expected error: TensionCompressionDriver.log will display: No truss elements have been assigned the Tension only or the Compression only beam type property - no analysis has been run.
  3. All load cases have to contain loading. Expected error: TensionCompressionDriver.log will display: Direct Accesss file TC_520131104_100759_R2.SIN was not foundat DNVS.Sesam.SifFramework.IO.SifStreamFactory.OpenDirectAccess(String path, Boolean readOnly)at DNVS.Sesam.TensionCompression.Driver.Program.RunThroughResultFilesAndMerge(String masterSinFile, Dictionary`2 slaveFiles)at DNVS.Sesam.TensionCompression.Driver.Program.MergeTheResultFiles()at DNVS.Sesam.TensionCompression.Driver.Program.Main(String args)

SIN file was not created for the specific load case, that does not contain any loading.

  1. Included load cases needs to have the highest FEM load case numbers.

Analysis will be Terminated. No file will be created.

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How to combine load cases with Rotation Fields?

Version: All

Load cases with different Rotation Fields can only be combined in GeniE if the Smart Load Combination option is On.

However, for some analyses the Smart Load Combination option must be off. In this case Sestra will not accept the load combination created by GeniE, because it has several BNACCLO cards for each node.

This can be overcome by creating the load combination in the Sestra input file itself using the cards SLCO, LCOM and optionally SCAL (if load factors are to be defined).

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How to create .FEM file for hydrodynamic added mass analysis in Sestra

The implementation of added mass in Sestra requires the wet surface to be a single superelement consisting of three and four noded membrane elements with all nodes super (all translational dofs retained and all rotational dofs free) and coupled to structural nodes (in other superelement). Since GeniE currently can't define all nodes as super (retained), and Patran-Pre doesn't support membrane elements, the following procedure must be used to prepare the model with all membrane elements and all super nodes:

  • Export a T-FEM file of the wet surface from GeniE with membrane elements.
  • Export exactly the same model once more but with regular shell elements. Use a different name for the T-FEM file.
  • Read the model in #2 into Patran-Pre and define all nodes as restrained nodes (translational dofs = restrained, rotational dofs = free). Export T-FEM file with new name.
  • Check that element and node IDs are identical in the T-FEM files created in #2 and #3.
  • Copy the lines that contain the restrained nodes from the T-FEM file in #3 into T-FEM file #1
  • Change the value of NDOF on all BNBCD cards from 6.00000000E+00 to 3.00000000E+00 and remove the values for the rotational dofs, i.e. replace:
BNBCD 1.46100000E+03 6.00000000E+00 4.00000000E+00 4.00000000E+00
      4.00000000E+00 0.00000000E+00 0.00000000E+00 0.00000000E+00

with

BNBCD 1.46100000E+03 3.00000000E+00 4.00000000E+00 4.00000000E+00
      4.00000000E+00

using replace functionality in a text editor.

  • Use T-FEM #6 for added mass. Use T-FEM file created in #2 for structural strength.

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How to obtain modal participation factors in Sestra?

Version: All

Runing Sestra from batch file or Sesam Manager

This is achieved by setting the MOLO parameter on the CMAS command to Sestra equal to 1. Note that the Implicitly Restarted Lanczos method cannot be used for this and the Lanczos method should be used instead.

To see the results, you need to open the results SIN file in Framework. Then, simply click Print > Modal Mass. You can then select the mode shapes for which you want the participation factors (e.g. include all). Next you click Apply, which will show you the resulting modal load factors in x, y and z per mode shape.

Using GeniE 7.2-07 or later:

You can get the modal participation factors directly from the report (FEM Results > FEM Modal Mass Factors) after running an eigenvalue analysis (except Implicitly Restarted Lanczos method).

Using GeniE 7.1-12 or older:

You can follow the attached FAQ document for the procedure.

Please see the attached document 00003704 Obtain modal participation factors.

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Increase eigen solver convergence by specifying maximum number of iterations

Increase eigen solver convergence by specifying maximum number of iterations. Sometimes, for dynamically not sound models, Sestra program may report an error message says the converged eigenvalue number is less than user required, as following,

ERROR Execution failed!

Eigensolver did not converge to within the desired tolerance. Maximum number of iterations reached. Only 37 eigenvalues converged to within specified tolerance 1e-07 (50 eigenvalues are requested). When this error occurs, increase the maximum number from the default 10 to 50 of Lanczos iterations will often get the problem solved, as following,

PS. Notice that COMM needs to be removed for Sestra to read the EIGA command. All commands are described in the Sestra user manual.

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invalid map<K, T> key error message

This is an unexpected error in Sestra, so there is little or no detailed description to document. One possible reason that can cause this mapping error is normally due to the lack of system memory. Please try the below steps and see if it can make the analysis to run:

  1. Turn off use of Sestra 10. This will make the program uses Sestra 8.8 for the analysis. The analysis time will be longer, but no memory issue and the error message (if any) will be clearer. In some cases, the error message will point out where the structure is not connected that could cause the mapping to fail.
  2. Try to run the analysis with a computer with larger RAM memory and available hard drive space.
  3. Increase the Windows paging file size (to the order of 64Gb), make sure plenty of hard drive space will be available during the analysis.
  4. Also try to add a SOLV command in the Sestra input file when running Sestra 10. This command will allow the program to process less load cases per time into memory and set NUMLC = 10% of all load cases. This will reduce the usage of memory during the analysis.

If none of the above works, please:

  1. Send us the analysis model files and we will try to replicate the issue.
  2. Let us know the computer configuration (especially the RAM memory amount and Paging file size settings).

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License error: invalid host when starting old Sesam programs (HydroD 4.10, Sestra 8.8, Profast)

License error: invalid host when starting old Sesam program (HydroD 4.10, Sestra 8.8, Profast) HydroD4.10, Sestra 8.8, Profast, and some other old Sesam programs, are not compatible with the latest dongle driver on some windows systems. The walkaround is to downgrade the dongle driver to 11.15.

  1. Delete the HASP folder in registry editor, as shown below. This will uninstall the license dongle driver.
  2. Install License dongle driver 11.15, which can be downloaded from (copy link if not working)

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Mass information has to exist in structure model for load transfer and later strength analysis (Wadam/Sestra)

If you want to do load transfer in HydroD and strength analysis in Sestra, mass information has to exist in your structure model.

For the mass related issues, Wadam/HydroD will calculate inertial loads from the mass information. These loads will contribute to calculation of the global forces and motions.

Also the accelerations will be transferred into Sestra. When you do the structure analysis, Sestra will only use the acceleration load from Wadam and the mass from the structure model to add gravity effect. So, your structure model should have mass information, similar to the mass input in HydroD/Wadam.

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“Not Enough total memory” or “Unable to allocate sufficient memory” message

Version: All from 10.0

Below are example of Sestra error message found in Sestra.mlg file, regarding insufficient memory issue.

Example 1 :Not enough total (physical + swap) memory for in-core factorization (required memory is 4221 Mb; available total memory is 841 Mb). If running a static analysis with multiple load cases, reduce the number of load cases to store in memory at the same time. Otherwise, exit other processes and/or increase the size of swap memory and then restart Sestra.

Example 2 : *    Sestra was unable to allocate sufficient memory. * *    This error typically occurs when handling many load cases at the same time, especially for models with many elements. Consider whether your analysis can be run with low memory options (SOLV command) or split into multiple analyses; or consider increasing the virtual memory on your system. * *    Peak memory usage (physical / total): 27410 Mb / 84270Mb.*

For remedies for this issue,

Workaround 1-1 : Add SOLV card in sestra.inp with TMEM=1 (available from 10.7 version)

  • This enables low memory model. Sestra uses a smaller memory footprint at a modest reduction in performance.
  • For example, Sestra caches only n (instead of all) load vectors at the same time

Workaround 1-2: Add SOLV card in sestra.inp with both TMEM=1, and NUMLC (NUMLC is available from 10.2 version)

  • When using TMEM, devalue NUMLC=1 or static, and NUMLC=100 for dynamic time-domain analysis.
  • Try smaller value, less than 100 for dynamic analysis.

Workaround 1-3: Add SOLV card in Sestra.inp with FORCE=1 & OOC=1 (available from 10.2)

  • Default values are FORCE=0 & OOC=0, which is using in-core (in physical memory factorization).
  • This enables Out-of-core (utilizing the HDD) for matrix factorization, which requires less memory, but slow performance.

Workaround 2. Increasing paging files in windows setting.

For detail information for SOLV command, please refer Sestra UM and below is one from Sestra 10.16 version. Example Sestra.inp file (for static analysis) is attached.

Sestra 10.16 (released 05 Apr 2022) has been improved for performance of import of load interface files in low-memory model, and for memory footprint for static and dynamic analyses with long load histories, so it’s recommended to always use latest version of Sestra, especially for such cases.

Also, make sure that the computer has plenty free hard drive space left for temp files and paging files; normally, the free hard drive space shall be well over 300Gb.

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Printing springs reaction forces

Version: All

If you want to print reaction forces in spring supports then you may need to use CPRI card in sestra input file. Please check for the proper entries in the sestra user manual.

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Retracking one single sueprelement in heirarchy

Version: All

If you want to retrack results for one superelement in the heirarchy then RETR card may look as follows,

RETR 2. 2. 0. 0. 2. 1.

For further explanation, please see the user manual.

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Sestra 10 unexpected error message DNVS MoFa

During analysis of Sestra 10 program, sometimes it will report kind of error message starting with DNVS::MoFa. When this happens, it means an unexpected error occurs during analysis and together with model files, this error message should be reported to DNV support for further assistance.

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Sestra Tri Criterion

GeniE reports on elements that does not satisfy these criteria. It prints a warning message indicating element number and associated face, as well as the failing value. Sestra will not accept those elements and the analysis will not finish successfully.

For Triangles:

100*A - L2< 0

Where A is area, L is length of Longest edge

For Rectangles:

25*C - D < 0

Where C is the shortest diagnonal, D is the longest diagonal

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To force Sestra10 run in Sesam Manager

To force the new Sestra 10 to run the new solver, a /dsf switch is required.

  • If running the analysis from Sesam Manager, then need to add the /dsf switch to the additional argument field,

  • Or if running the analysis from command prompt, then the /dsf switch should directly follow the Sestra.exe command,

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Unable to find Sestra (32bit or 64 bit) in GeniE

Some users may experience this Warning!:

Unable to find Sestra (32bit or 64 bit) on location as defined in DNVS_ApplicationVersions.xml or on location SESAM_HOME in SESAM.INICould not read default version installation information for application Sestra from DNVS_ApplicationVersions.xml.

This problem should be resolved by installing Application Version Manager. You can use your Sesam DVD and install it from the Application Version Manager folder or, alternatively download it from Software Downloads in Customer Portal.

If you continue to get an error after this, first please ensure you have installed the latest version of Sestra from the Sesam DVD (located in folder Sestra or Sestra64).

Then, open GeniE, select File -> Set External applications and click Browse. Find the folder where Sestra is installed on your PC (typically it is located in C:\Program Files (x86)\DNVS\Sestra V8.4-04\bin) and select Sestra.exe.

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