Is there any method to omit portions of my input file and read in others? |
Yes, this can be done by enclosing the portion that you want to omit in an if-then statement.<br>Set the parameter OMIT in the beginning of your... |
QUESTION:
The inductance differ greatly by ANSYS7.0 and ANSYS8.1.
Which result is right?
ANSWER:
The 8.1 result is probably the correct one. I know of 2 bugs (descriptions appear below) that have been corrected that may be responsible for the difference you see at releases 7.0 and 8.1. If the model you see the difference in is 3D DSP, then it is likely that the second defect below is responsible for the difference you see.
1) Defect 14461: Error in LMATRIX with bfa
LMATRIX was not developed for solid model loads.
To allow LMATRIX work for the user problem with BFA load,
an undocumented BFASCALE command only applied in LMATRIX is developed. Note, this solution is not general and fully tested; it resolves the issue of this error report and let customers use LMATRIX with BFA load. We should come back to this issue later at development and address it with our rigorous verification procedures.
2) Defect 20637: DSP / Lmatrix incorrect with linear permeability
Incorrect inductance coefficients may be provided
by the LMATRIX command macro if both of the
the following conditions are satisfied:
- LMATRIX is applied after an operating (nominal) solution is computed
by the magnetic differential scalar potential (DSP) method
- the relative permeability of the magnetic region
is high (mur > 50,000).
The operating (nominal) solution computed by DSP method is correct LMATRIX provides correct numbers for mur < 50,000 after DSP method or if the operation solution is calculated by magnetic vector potential (MVP) methods (nodal or edge) regardless of mur values.
The following source changes were needed to implement
the new incremental DSP method:
scmgfl.F
el96.F
magma5.F
gtacti.F
LMATRIX.MAC
These tests have been added to the set to verify correct resolution: ev96-65s ev96-66
Results obtained after the code change look great. The 3D MSP inductances now agree very well with those obtained for 2D MVP and inductance asymptotically approaches a constant v |
QUESTION:<br><br>The inductance differ greatly by ANSYS7.0 and ANSYS8.1.<br>Which result is right?<br><br>ANSWER:<br><br>The 8.1 result is probably the... |
I am using the Redlich Kwong equation of state and I see that there is an option for
Redlick Kwong polynomial for Heat Capacity. What is this and how is the
Redlich Kwong Heat Capacity calculated? |
<br><br>The Redlich-Kwong heat capacity is calculated from the zero pressure polynomial valid for ideal gases<br>using analytical derivatives of the RK equation of state and the... |
I have a Plot3D grid that I created that I want to import into
CFX-Pre. I couldn't find the import filter at first, but finally
found that I could set the type to user import and point it
to ImportPlot3D.exe. When the file was imported,
however, all the boundaries were lumped into a single
2D region. I need to be able to set different boundary
conditions on different faces. What options do I have? |
<br><br>Support for the Plot3D format was discontinued some time ago for<br>CFX-5.<br><br>Files can still be imported, but the problem of setting... |
How do you apply an angular acceleration in Workbench 8.1? I believe
I did it correctly, but the solution does not reflect it. |
Workbench won't send material properties if it doesn't think they are<br>needed, so it may not have sent the density. You could add a small gravity<br>load to your... |
Why aren't the component stress results obtained with PLSECT and PLPATH
the same. They are mapped to the same path. |
PLSECT uses the path coordinate system, with x oriented in the direction of the<br>path, while PLPATH uses global cartesian. Your path is oriented in the global y<br>direction, so the... |
Why is my Multifield magneto-structural analysis with solid117 failing
in ANSYS 9.0 with a message about an incorrect degree of freedom? |
MORPH,ON is introducing the structural dof, ux, uy and uz. These are not<br>permitted in a solid117 analysis. [Ref: Defect 29008]
|
Why would the command SUMTYPE,PRIN affect a single result set?
It is more pronounced in cases of large strain. |
When SUMTYPE,PRIN is set the component stresses are zero. This<br>behavior could affect nodal averaging.<br><br>With the default SUMTYPE,COMP you are averaging the component... |
Is it possible in Workbench 8.1 to retrieve the forces
between the contact and target forces in a contact pair? |
Yes. You can insert "Reactions" into the Contact Tool.
|
Q. I run a batch file to create an FEA model and run it with FLOTRAN. The results differ depending on whether or not I put a SAVE/RESUME in the input stream before the SOLVE. Why is this?
A. You must be using the SPARSE DIRECT solver for pressure! The save/resume is required for such cases. If you use the default solver (PCCG) this will not happen, and the results will be the same regardless of whether or not the save/resume is there. |
Q. I run a batch file to create an FEA model and run it with FLOTRAN. The results differ depending on whether or not I put a SAVE/RESUME in the input stream before the SOLVE. Why is... |
Given a line meshed with, say, 100 beam elements, how can I apply a
tapered pressure from one end of the line to the other? SFBEAM is per element
(doesn't span all elements), and SFL is meant only for edges of areas.
The user wants to stay with a distributed load (pressure) and doesn't want
to apply nodal forces. |
You could use SFBEAM with a table load as in the attached... |
Why are the maximum ANSYS 8.1 PSD SEQV values 2-3 time higher than
a competitor's? |
It doesn't seem to be an issue with how SEQV is computed from the 1 sigma values,<br>because the component shear stress is very high also - around 9000 psi - so an<br>SEQV value... |
Why is there is a limit of a 1km box in DesignModeler and Simulation?
For most structural/thermal solutions this is not a major problem. However, for a MEMS device it is common to
use micro or nano length units (which are presented as meters to Parasolid to avoid Parasolid converting them
back to meters.) This can easily result in dimensions greater than 500. |
This is a limit in Parasolid. The 1000 meter limit is centered at the origin, so a model dimension cannot exceed<br>500 meters in any direction. Simulation uses the Parasolid engine during... |
Why am I having difficulty with convergence in the initial 9.0 release of
Workbench with ramped loading over multiple load steps? |
Forces and non-zero displacements are being deleted between load steps,<br>so their value is ramping from zero instead of the value in the previous load<br>step. In addition to... |
Why does the Block Lanczos solver either not converge or
give erratic results (e.g., frequencies change with element size)
for this piezoelectric model? |
There are two independent volt domains used as piezoelectric<br>actuators on the top and bottom of a solid185 beam. Their terminals<br>have been coupled in volt, but no voltage... |
Is there a physical meaning to the displacement at the master
node of an RBE3 definition? This is the dof that is removed. |
Yes, the displacements are the average of the retained dof.
|
I defined remote masses with local coordinate systems in the intial 9.0 release
of Workbench. Why are they being mislocated during solution? |
There is a transformation error in this release when the local coordinate system directions<br>are not aligned with global cartesian [Ref: Defect 29563]
|
Why am I running out of memory using the ADAMS macro at 9.0?
The same model ran at ANSYS 8.1. |
There is an error in memory allocation for the element reordering.<br>A workaround is to use the undocumented BCSOPT,MMD, command which uses an<br>alternate element reordering routine.
|
Can you recommend workspace settings for a user who is running in ANSYS 8.1 in batch mode on a machine with two 1.5 GHz Itanium 64 Bit processors, running Windows XP 64-bit. It has 12 GB of RAM available. He previously ran large models in 6.1 using the -m and -db options, and everything worked fine. Now in 8.1, if he uses similar settings he receives a warning message, "...autosizing cannot allocate the needed memory..." and a page file is created.
The user does not want a page file to be used. Could you please provide more details on how and when to use the -f switch? In particular, what suggestions can you make to optimize performance with his 12 GB of RAM? |
Answer from development:<br>The problem with Windows 64 is that the dynamic memory allocation does<br>not work like in all the Unix and Linux versions we have. So, a user can... |
What are the typical thermal units in ANSYS? |
The following are the typical thermal units in ANSYS in the SI and English systems:<br><br>Typical Units in ANSYS ( SI ):<br>Temperature Degrees C ( or K )<br>Heat Flow ... |
Is *.DFX geometry file import from AutoCAD into ANSYS available and if not what are my options? |
The AutoCAD DXF (Drawing eXchange Format) is not a supported format for importing into ANSYS. For the supported CAD formats, see the ANSYS Connection Users Guide. The recommended method of... |
How can I write/export a mesh file out of ANSYS to another program? |
ANSYS does not have a translator to produce a mesh file in the format of other programs. However, ANSYS does have commands to write out mesh information in a general text format. Your options... |
Can I undock and move the input window to a different part of the screen? |
Yes. the input window can be undocked from the ANSYS GUI by clicking on the "ANSYS Command Prompt" (keyboard-looking) icon to the left of the input window. This will allow you to... |
Can I get the distance between two displaced nodes? |
Yes, use the UPCOORD command to update the coordinates to their displaced locations, then use a get function.<br><br>The Macro shown here can be used to calculate the distance between... |
There is no option in the ANSYS GUI to change the number of a node, is there a workaround? |
Yes, follow this procedure:<br><br>1) Get the x, y, and z location of the existing node.<br>2) Create a node with the new node number at the same location using the N... |