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Why is my transient analysis with CMS superelement aborting?


The issue may be related to defect 76683, which has been fixed for ANSYS 12.0. This error was caused by a conflict between the HHT time-integration scheme and the internal nodes created for the...

Why does the Point Mass feature in Workbench (WB) Simulation require so much memory?


This is due to the use of a consistent-mass matrix formulation. A remote mass in WB is simply a set of contraint equations (CEs) in ANSYS. When this remote mass is connected to many nodes (i.e.,...

In the Workbench Fatigue Module at Release 11.0, how is strain-based fatigue calculated?


The Workbench Fatigue Module uses Neuber's rule to convert elastically, calculated stress, and calculated strain to total stress and strain. According to Neuber¿s rule, the total...

I am doing a nonlinear static analysis with substructures in version 8.1. The models that solved in v8.1 without any problem now abort in v11 (ANSYS has requested more scratch space than currently available) on 32-bit hardware with 2 GB of memory (Windows 2000 and XP). Can the v81 behavior be reproduced in v11?


The error is occurring because of the superelements in the model. There are four copies of the superelement matrices in memory during the assembly process. For normal elements, this is only a few...

In ANSYS Release 11.0, what is KEYOPT(4)=1 for SHELL63?


KEYOPT(4)=1 for SHELL63 is an old KEYOPT that pre-dates Release 4.4. It controlled how the edge stresses were printed. It is now undocumented and does not have any affect.

In ANSYS Release 11.0, how does ANSYS convert integration-point results to nodal results?


The ERESX command controls the conversion of integration-point results to nodal results. The behavior for each ERESX setting is explained below.<br><br>DEFA - If element is fully...

In ANSYS Release 11.0, why does the STAT command list two reference coordinate systems for the CMOMEGA command?


The first reference coordinate system is used for the velocity (CMOMEGA), while the second is used for the acceleration (CMDOMEGA). The second will be listed even if the CMDOMEGA command was not...

Is Workbench FEModeler exporting NASTRAN deck with dropped mid-side nodes incorrectly? Everywhere a dropped node is referenced in the element definition, it has the #4294967295. These should have a definition of blank or 0. When all occurrences of the #4294967295 are replaced with 0s, everything is fine.


This was fixed under defect 62668 for ANSYS 12.0.

I am trying to run a case where I am using a stage interface to make a connection between
rotating and stationary meshes. The pitch angle is different on the two sides and I used the specified pitch angle option.

When I try to run the case, I get a warning message that says that one side of my interface seems to contain a zero radius and that I should set the transformation type to None and am not sure what this refers to.

Also, I have had cases where my run failed at the partitioning stage with the error message indicated that a transition between +/-180 degrees could not be found on one side of the interface. When does this error message occur and what can I do as a workaround? - KSVIHLA


The Transformation Type message refers to outdated solver CCL which has been deprecated since ANSYS CFX 11.0 and can safely be ignored.<br><br>As you note, you should directly specify...



I am running an ideal gas case with energy sources and sinks and am seeing sustained oscillations in the enthalpy
and mass imbalances about zero that are preventing me from using a larger time step.

I've been told that enabling temperature damping may help. How do I do this?


<br><br>The following CCL needs to be added to the Solver Control object to enable temperature damping:<br><br> SOLVER CONTROL:<br> TEMPERATURE...

Can I change the information in the ANSYS legend?


Not directly, but you can save a file in the ANSYS neutral graphics format (/SHOW,filename), which is stored in plain text, and then edit the labels in the file with an editor. Then, you could...

Why is this small piezoelectric harmonic analysis very slow when a CIRCU94 element is added?


This was reported in defect 63164. In the output, there is a message that "pivoting" has been activated. Pivoting is a solver technique used when the matrix is determined to be...

Do you have an example of a moving magnetic probe?


Instructions on how to create such probe can be found in the attached presentation file.

In ANSYS Release 11.0, is it possible to capture all six rigid-body modes in a free modal analysis of a shell-to-solid models with MPC contact?


Yes. Failure to capture six rigid-body modes is usually caused by artificial internal constraints. The solid-to-shell option for MPC contact should eliminate those artificial constraints. That...

In the Workbench Fatigue Module at Release 11.0, how is the damage related to the safety factor?


The damage and the safety factor are reciprocals. The damage is the predicted cycles divided by the allowable cycles, whereas the safety factor is the allowable cycles divided by the predicted...

How can I apply different PSD excitations in the x and z directions in Simulation 11.0?


You could use commands like the ones below in a Commands Object in the Random Vibration branch.<br><br><br>cmsel,s,fixedsu ! Predefined nodal component for all fixed...

In ANSYS Release 11.0, can tabular boundary conditions be used in a reduced transient analysis?


No. Tabular boundary conditions are valid only in static, full transient, and modal-superposition analyses. Tabular boundary conditions cannot be used in a reduced transient analysis. That...

Why does my harmonic-response analysis abort at 500 substeps? I thought the default limit was 1000 solutions?


Each harmonic substep writes a real and an imaginary set of results, so you hit the default 1000 solution limit (/CONFIG,NRES,1000).

I am running a case with a transient rotor stator interface. If I run it in serial, it requires about 4 GB to run. If I run it in parallel with six
partitions with the default partitioning scheme, the memory allocated by the solver increases to 16 GB.

What is causing this inordinate increase in memory over that required for a serial run? - KSVIHLA


At 11.0, transient rotor stator interfaces can be costly in terms of memory overhead when run in parallel due to the<br>large number of overlap nodes at the partition boundaries which can...

In the Workbench Fatigue Module at Release 11.0, what is the maximum calculated safety factor?


The maximum calculated safety factor is 15.0. The user cannot change that limit.

Is there an error in the Harwell Boeing dump (HBMAT) of a superelement in 11.0?

I understand that matrices from SUB files are dumped completely, regardless of whether the matrix is symmetric or unsymmetric or whether there are zero-values. I also understand that the offset of 1 in the column pointer array at the beginning of the file has been fixed in ANSYS 11.0. However, I think that there still is a bug: when I try to dump for example a 6x6 superelement matrix, the column pointer array should read as follows: 1, 7, 13, 19, 25, 31, 37 with the corresponding row indices 1, 2, 3, 4, 5, 6 for each column. The column pointer array ANSYS produces is instead 1, 7, 13, 19, 25, 31, 32. Therefore, any read-routine that has implemented the HB format correctly, will fail to read in the correct matrix.


Yes, you are correct. The error has been fixed in 12.0.

In Workbench Simulation Release 11.0, is it possible to apply rotational velocity to a portion of the model?


No. Only one rotational velocity can be specified and it must be applied to the entire model. However, applying a rotational velocity to a portion of the model is supported in ANSYS (CMOMEGA...

Why is my random-vibration (PSD) analysis failing on second PFACT?


You may be hitting defect 60605. MPC contact is not being treated correctly for the second and subsequent PFACT commands. The error has been fixed for 12.0.<br><br><br>Defect...

How would I create a response spectrum for a time-history? I have run a transient analysis and am trying to use the RESP command to generate the equivalent response spectrum. The input is a sine wave with an amplitude of 0.025 inches. In POST26, the node where the loading was input has the correct displacement versus time, a sine wave with an amplitude of 0.025. I then use the RESP command to generate a displacement response spectrum. When I plot displacement versus frequency, I would expect to see one vertical line with an amplitude of 0.025 at a value of 1 Hz, but I do not see anything at all on the graph.


No, other frequencies will be excited by the 1 hz excitation. I have written below how you would create a response spectrum for this case. The response spectrum created shows that a structure with...

Is it possible to extract modes for SOLID65 in a damaged state? I would like to do a modal-superposition analysis (for seismic evaluation) on our concrete pool structure in its damaged state. Is it possible to extract modes from a tangent stiffness matrix at any point in a nonlinear analysis?


It is possible to extract modes based on the tangent stiffness matrix using the large deflection, prestressed modal procedure [PSOLVE,EIGLANB], but the modal results cannot be used in a subsequent...