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Pulsatile Flow Blood Vessel

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Old   July 18, 2013, 03:45
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  #21
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Matthias Vo
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Quote:
Originally Posted by omni89 View Post
*** WARNING *** CP = 257.948 TIME= 18:38:51
There are 1031 small equation solver pivot terms.
This is bad but could stab. when the simulation progresses.
Quote:
Originally Posted by omni89 View Post

*** ERROR *** CP = 260.397 TIME= 18:40:00
One or more elements have become highly distorted. Excessive
distortion of elements is usually a symptom indicating the need for
corrective action elsewhere. Try ramping the load up instead of step
applying the load (KBC,1). You may need to improve your mesh to
obtain elements with better aspect ratios. Also consider the behavior
of materials, contact pairs, and/or constraint equations. If this
message appears in the first iteration of first substep, be sure to
run shape checking of elements.
Your mesh is folding. Try this here
Quote:
Originally Posted by omni89 View Post
The pressure wave I'm using now is an actual pressure wave seen in the blood,
so it's equation is lengthy in order to form an accurate waveform (refer to the
attached image). Is the error in the Ansys part occurring because of a meshing
problem?
How/what is monitored? The folding basically refers to the actual structural solution. There is "to much" going on.

Did you try the under-relaxation? How is the density ratio fluid/struct.?

Last edited by mvoss; July 18, 2013 at 07:38.
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Old   July 26, 2013, 15:04
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which material characteristics are you using for the wall?
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Old   August 28, 2014, 12:11
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Raj
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Hi,
I am also working on the same topic but I am having problem in the initial stage of the analysis. I have the geometry but I am unable to go to Modeler to do the meshing of the wall of the blood vessel.

1. This is the geometry of my model.
2. Fluid Domain
3. Surface of the blood vessel
4. Modeling error in the workbench

Can anyone help me solve this problem?
Attached Images
File Type: jpg Geometry.jpg (84.8 KB, 14 views)
File Type: jpg Geometry- fluid domain.JPG (89.6 KB, 13 views)
File Type: jpg Geometry- surface.JPG (77.0 KB, 13 views)
File Type: jpg Workbench error.JPG (27.4 KB, 15 views)
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Old   August 29, 2014, 08:11
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How did you mesh the wall area? You need to give some info about the error in the meshing, otherwise its hard to tell what the problem is.
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Old   August 29, 2014, 09:59
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I am not able to start the meshing. The last image is showing the workbench view. I tried refreshing, updating the project but nothing worked. Neither wall not he flow domain is available for meshing.
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Old   August 29, 2014, 11:26
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So you dont see any geometry when entering the ANSYS meshing environment? Not sure, but this could be due to the very small features. You could scale it up in the Design Modeler and scale it down after meshing. Try smth. bigger, like 1000m, to see if this is passed onto the meshing.
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