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In what form is stress vs. strain data entered for Multi-linear Isotropic Hardening?


In ANSYS Release 10.0, all stress-strain input and results (for large strain solutions) is terms of true stress and true strain.

Can parameters and components have the same name?


In ANSYS Release 10.0, parameters cannot have the same name as components (see documentation for *SET command).

How to superimpose an alternating pressure condition onto a steady-state thermal condition in the WB fatigue module?


In WB Release 10.0, you need to specify two Environments.<br><br>E1 = steady-state thermal + ½ pressure<br>E2 = steady-state thermal ¿ ½...

Why is medium size PSD analysis aborting in ANSYS 10.0?


The problem is that there exist 2 PSDs: a nodal PSD and an (unused) spatial PSD. We were checking<br>all defined PSDs and therefore going down the spatial PSD path and getting confused. ...

How is the Kf term used in the WB fatigue module?


In the WB fatigue module Release 10.0, Kf is simply used to adjust the calculated alternating stress value for the fatigue calculations. The allowable number of cycles for a particular loading...

Can you specify a constant damping ratio for a modal analysis?


In ANSYS Release 10.0, you cannot specify a constant damping ratio (DMPRAT) in a modal analysis. However, you can specify material damping (MP,DAMP). DAMP is a multiplier of the stiffness matrix...

What is Power Graphics plotting for USUM at ANSYS !0.0 in a structural transient?


In ANSYS 10.0 with power graphics on, PLNS,USUM is plotting UX (Ref: Defect 40247)<br>This is corrected in 11.0. A workaround is to use FULL graphics (/GRAPH,FULL.)

Why am I getting the error message below about too many blocks per tag in ANSYS 9.0?

*** FATAL *** CP = 63.650 TIME= 12:20:17
Internal memory manager error during solution (too many blocks per
tag). Please report this system error to your ASD or ANSYS, Inc.


This is due to the fact that in the USE pass with 28 superelements and no other elements,<br>we were not properly handling the fact that instead of having a sparse matrix to assemble...

Can external body loads be applied on elements involved in inter-field load transfer in the MFS?


In ANSYS Multiphysics Release 10.0, the MFS cannot correctly accommodate applied external body loads and inter-field body load transfer on the same set of elements. The MFS inter-field transfer...

Is there any way to model volumetric attenuation in an acoustic model? I have a
wave propagation analysis in a dissipative and dispersive medium. How can I input wave
attenuation coefficients?


There is no material property of the acoustic elements (FLUID29/30) to represent acoustic<br>attenuation, but I found that a transient acoustic analysis was damped by alpha and beta...

How does specified thickness affect results in a plane stress analysis?


In ANSYS Release 10.0, the thickness affects the in-plane stiffness for plane stress elements. The element stiffness is the volume integral of the transpose of the B matrix multiplied by the D...

Is there any way to speed up the SENERGY macro? It is way too slow.
I specified SENERGY,0,1 to calculate the magnetic energy in POST1, but I
stopped the calculation after 3 hours since it seemed that the calculation
needed even more time.

The model solution time is only about 30 mins, so why does the SENERGY
macro take so long?


Sometimes postprocessing of large results files is slower than the solution,<br>but this seems excessive. One trick to speed up postprocessing is to enter ansys<br>with a large -db...

How to calculate the modal mass and modal stiffness?


In ANSYS Release 10.0, you can use the kinetic energy to extract the modal mass. ANSYS normalizes the mass, so the modal mass matrix is an identity matrix and the modal stiffness matrix is a...

Why is my non-cyclic load being applied as cyclic (same direction relative to each sector?)


Your applied forces are only to the sector edge nodes since you unselected mid-side nodes and have a one<br>element wide sector. This is why your applied forces are being applied...

In a random vibration analysis am I limited to 1000 modes?
Based on the description of the SPOPT command, I believe I am limited to using no more than
the first 1000 modes from the modal analysis. Is this correct, or is there a way to increase the
number of modes that can be used for a PSD analysis?


Yes, you are limited to 1000 modes. As a workaround you could do a second psd with modes<br>1001 and higher and SRSS the 1 sigma results.<br><br>Keep in mind, the psd...

How much memory is available for the SPARSE solver on a WIN32 system?


In ANSYS Release 10.0, the SPARSE solver requires a contiguous block memory. You can never get more than 2 GB in a single block, and because of the way that WIN32 fragments memory, the maximum...

Is it possible to include thermoelastic damping in a modal analysis?

I've been able to successfully use plane223 and solid226 elements to model thermoelastic
damping in a MEMS device. (In a very short period of time I've been able to duplicate and
then extend the work of colleagues using another package.) As in the documented example,
I've used a harmonic excitation input. However, I would also like to repeat the analysis by
using the eigenvector solution as the strain energy input. (Similar to ref #1)


Yes, you could use the damped modal solver accessed with MODOP,DAMP. This solver is quite<br>slow, so we typically don¿t recommend it, however, the more robust and much faster damped...

What is the limit for element and node numbers?


In ANSYS Release 10.0, the limit for element and node numbers is 99,999,999. The limit for attribute numbers is 9,999,999 (see Section 1.4.3 of the ¿Commands Manual). ID numbers larger...

What element normal is used by EREFINE?


In ANSYS Release 10.0, the EREFINE command uses the SHELL element normal of the highest numbered element, not on the normal of the underlying element. This behavior was reported in defect...

Why can't I access the Goal Driven Optimization Feature in Design Explorer?
It appears you need at least one design variable (which appears to 'unlock' the goal driven optimization button)
and at least one random variable (which appears to 'unlock' the design for six sigma button.) Can you
confirm this?


Yes, you are correct about the need for a random variable and a design variable to do a ¿robust design.¿ A robust design is<br>an optimization in which the objective function...

Is there any way to specify a pressure to simulate water in a membrane?
The hydrostatic pressure will be dependent on the displacement.


I tried specifying a negative elastic foundation stiffness with shell63, but it doesn¿t work.<br>Perhaps you could apply COMBI14 elements with a negative spring stiffness all the...

Why does the RDSF command create incorrect radiosity surface elements on the outer surface
of this SOLID70 brick mesh in ANSYS 10.0?

The input below generates SURF252 surface effect elements that appear to be internal to the volume.

block,0,.1,0,.1,0,.1
et,1,70
esize,0.02,

vmesh,all
allsel

asel,all
nsla,s,1
nsel,s,ext
sf,all,rdsf,.8,1
alls

rsurf,defi,last,2

esel,s,enam,,252
nsle,s
eplo


This was Defect 38120. It occurs when the entire outer surface of a brick mesh is flagged. It is fixed in 11.0.

Is there any way to use discrete variables in Design Xplorer?


Not in 10.0. Development has the following procedure to do it in 11.0:<br><br>The parameter manager in 11.0 allows you to use suppression properties in<br>conjunction with a...

How can you compare ANSYS results to ASME Code stress intensity limits?


In ANSYS Release 10.0, you can use the PRSECT command to linearize the total stress along a path. Linearizing decomposes the total stress into the membrane, bending, and peak stress components. ...

What is the sign convention for SHELL181 edge moments?


The sign of shell edge moments is based on the sign of the bending<br>stress they produce at the top surface. The moments satisfy<br>the equations SX(TOP) = 6*MX/T**2 and SY(TOP)=...