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Why are moment reactions not exact for complex Simulation 11.0 models?


The main source of this error in recent experience has been due to penalty-based contact across open gaps, particularly across curved surfaces. A moment constraint is produced. A model integrity...

How to apply PSD/random vibration excitation in 3 directions simultaneously?


The input file below applies three psd spectrums simultaneously.<br><br>/SOLU<br>ANTYPE,SPECTRUM<br>SPOPT,PSD<br>DMPRAT,0.02 ! 2%...

How can I plot the material colors of each layer of a composite element in ANSYS 11.0? I am using SOLID46.


It isn't possible with SOLID46, but you can with SOLID185 using the sample input...

Why is ANSYS 11.0 aborting when I request stresses for this beam model using a complicated user-defined section? The db model contains only 4 beam 189 elements with a user-defined section assigned to them. Simple sections work fine but this one causes ANSYS to crash. I am working on an x64 with 16GB of ram so memory should not be a problem.


This is indeed due to the very large number of elements in the mesh used to create the user-defined section. The error number is defect 60629 and it is fixed in ANSYS 12.0.

If I select all elements and unselect the contact elements, I get one volume. If I leave the contact elements in, then I get another answer. Where does this contact element volume come from?


Many elements have "VOLU" as an ETABLE quantity; however, the name can be misleading. For some, the element area is stored in the common label "VOLU" (182, 183, 154,...

Do you have a very simple example of CMS superelements used in a modal analysis?


Yes, here is an input file that compares a full modal solution with a CMS superelement modal...

How can I apply a boundary where ux=uy on a plane in Simulation 11.0?


You can use a remote displacement as demonstrated in the attached database.

Why are ETABLE forces zero for Simulation 11.0 spot welds? I have a model that is held together by spotwelds, and I want to use ETABLE items to extract FX in the beams used to model the spotwelds. I resume the model in classic, read results, isolate BEAM188 elements, and create an ETABLE items with SMISC,1. When I list this ETABLE item, the forces are all zero.


The Simulation 11.0 default solution output to the results file doesn¿t include ETABLE items. Try adding a command snippet with OUTRES,ALL,1.

Why am I getting the error message below about negative permittivity for this piezoelectric property?

*** ERROR ***
The calculated permittivity at constant strain matrix [epS] for
material 1 has negative diagonal terms.

MATERIAL INPUT ASSOCIATED WITH TB,DPER COMMAND FOR MATERIAL NUMBER 1

Dielectric (relative) permittivity at constant strain
computed from piezoelectric strain and stress matrices.

EP11 EP22 EP33 EP12 EP23 EP13
-69.025 52.629 0.0000 0.0000 0.0000 0.0000


Looking at the manufacturer's data, the set of compliance coefficients is incomplete and is inconsistent:<br>- s12 and s13 are missing and are assigned small values<br>- s11 is...


I have defined Named Selections in DesignModeler but they are not transferring into CFX-Pre. I used Meshing Application under Workbench.


<br>The following applies to Workbench version 11.0.<br><br>They are several reasons why Named Selections in DesignModeler may not transfer to CFX-Pre...

Under the definition for nominal design stresses for materials, what exactly is Re and Rm? Also, what does it mean by nominal design stress? Is it an input by the user? How does the user input this value?


Re and Rm are respectively the yield stress (stress before plasticity occurs) and the ultimate strength (when the part breaks). They are standard values for a material description and are to be...

Under stress admissibility criteria, there are four options. What is the difference between total resulting stress and total primary stress? What is local and general primary membrane?


The general and local membrane stresses refer to the local and general areas in your model (look under named selections to see where the areas are). The local areas are the ones close to...

Under stress admissibility criteria, there is a "coefficient" and "max coefficient". How do we use these to determine if it passed the code checks?


The coefficients come from the norm. The max you see is the maximum of each stress. The Cf is the coefficient multiplied by either the nominal stress, Rm or Re (depending on the norm).

Is shell the only element support in the pressure vessel module?


No, your model can mix solids and shells and even beams, but the norm calculation will only apply to the shell parts of your model (we plan to extend this to solids in future versions).

Can I create my own CAD model and bring it into simulation to use with the pressure equipment module?


Yes, but make sure you have some shells in your model and that the "general_area" and "local_area" are defined.

How can an axisymmetric model be visually expanded to 3/4 model?


In ANSYS Release 11.0, the /EXPAND command can be used to create graphic display that is larger than represented by the actual finite element model. The input file below creates a 2D axisymmetric...

How can a 1/4 symmetry model be visually expanded to a 3/4 model?


In ANSYS Release 11.0, the /EXPAND command can be used to create graphic display that is larger than represented by the actual finite element model. The input file below creates a 1/4 symmetry...

Producers of piezoelectric crystals give material data like compliance or stiffness for open and closed circuit condition. Which data should be used for input in ANSYS for anisotropic material?


ANSYS accepts stiffness/compliance terms measured under zero electric field conditions (closed-circuit). This is the [cE] matrix in Eq. (11-37) of the Theory Reference. Our input supports two sets...

How can a finite element mesh without a solid model be reflected?


In ANSYS Release 11.0, a finite element mesh can be reflected by first reflecting the nodes using the NSYM command and then reflecting the elements using the ESYM...

When temperature-dependent material properties are defined, how does ANSYS determine the material property if the calculated temperature is greater than the maximum temperature defined on the material curve?


In ANSYS Release 11, if the calculated temperature exceeds the highest defined temperature for a temperature dependent material curve, ANSYS uses the maximum defined temperature to determine the...

Is it possible to plot principal stresses from a PSD (random vibration) analysis?


In ANSYS Release 11.0, it is not possible to plot principal stresses from a PSD analysis. The capability to plot of principal stresses from a PSD analysis was removed in Release...

In a PSD (random vibration) analysis, must the database be saved before using the time history post-processor (/POST26)?


In ANSYS Release 11.0, you must save all information after a PSD analysis before exiting ANSYS. All PSD information must be saved or it will not be possible to completely post-process all results.

How to apply initial stress using INISTATE?


In ANSYS Release 11.0, initial stress can be applied using the INISTATE command. The example below is a simple tensile bar. It is solved twice.<br><br>The first solution has one load...

Is it possible to directly refine the mesh without having a solid model?


In ANSYS Release 11.0, the finite element mesh can be directly refined using the EREFINE command (see input file...

Is it possible to transfer a model from WB Simulation to ANSYS?


In WB Simulation Release 11.0, there are at least four methods available to transfer a finite element model from WB Simulation to ANSYS. These methods will transfer the finite element model to...