I'm trying to do some thermal analysis on some very high aspect ratio structures. For example, I'm considering a circular plate that is 10 microns thick and a diameter of 2cm subject to a fixed temperature along the outer radius and a point heat load somewhere on the plate.
When I start the thermal analysis I get a warning that says: "The highlighted point heat loads can cause singular temperature gradients." Then Pro/Mechanica never seems to complete the "Creating solid elements..." (I've let it run somewhere around 5 hours and finally gave up.) Below is a listing of the run status.
In the status it does say that the max allowable aspect ratio is 30.0. I assume this is in reference to the aspect ratio of the individual elements. Is there anyway that I can change this?
If the plate is made thicker (say 500 microns) it works great. Also, if I remove the point heat load and use two different prescribed temperatures it worked.
Thanks for any help!
Mike
------------------------------------------------------------ Pro/MECHANICA THERMAL Version 24.8(823) Log for Design Study "test" Wed Dec 10, 2003 11:25:14
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Begin Creating Database for Design Study Wed Dec 10, 2003 11:25:14 Elapsed Time (sec): 0.61 CPU Time (sec): 0.24 Memory Usage (kb): 24924 Work Dir Disk Usage (kb): 0 ___________________________________________________________
Pro/MECHANICA External Database Interface - MNF_TO_MDB Translator Copyright(c) 2002PTC (tm) - All Rights Reserved
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Global Information:
Model Name: .\test\test Product Name Undefined Product Version 24.8
Creation Date 12/10/03 Creation Time 11:25:14 Author UNKNOWN
Header Information:
MNF Version 24.8 MNF Author mechxfce Date of MNF Creation Not available Import Mode ptc Name of Original Model Not available Comments Not available
Error / Warning Reports :
Translation Error/Warning Summary
Total errors: 0 Total warnings: 0 Total informational messages: 0
**** Entity Creation Summary ****----- Summary Information -----
Description Entities Entities Found Created
Groups 3 3 Coordinate Systems 2 2 Parts 1 1 Points 3 3 Curves 11 11 Topological Edges 6 0 Surfaces 4 4 Surface Curves 12 0 Surface Regions 4 4 Volumes 1 1
Translation Elapsed Time
*** 0 seconds ***Step Elapsed Time (sec): 0.13 Step CPU Time (sec): 0.13
Begin Integrated Mode Error Checking Wed Dec 10, 2003 11:25:14 Elapsed Time (sec): 0.74 CPU Time (sec): 0.36 Memory Usage (kb): 33188 Work Dir Disk Usage (kb): 0 Checking the model before creating elements... These checks take into account the fact that AutoGEM will automatically create elements in volumes with material properties, on surfaces with shell properties, and on curves with beam section properties.
Step Elapsed Time (sec): 0.05 Step CPU Time (sec): 0.05
Begin Generating Elements Wed Dec 10, 2003 11:25:14 Elapsed Time (sec): 0.79 CPU Time (sec): 0.41 Memory Usage (kb): 33188 Work Dir Disk Usage (kb): 0
Copying elements from an existing mesh file ... The meshed study model is geometrically incompatible with the current model. Only copied 64% of the elements. The model must be remeshed. Element copy failed. Pro/MECHANICA will automatically remesh.
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AutoGEM Settings
Isolate Surface Features:
[x] Reentrant Corners [x] Point Loads [x] Point Constraints [x] Point Heat Loads [x] Point Prescribed Temperatures [x] Point Convection Conditions------------------------------------------
[x] Insert Points [x] Create Links Where Needed [x] Move or Delete Existing Points [ ] Modify or Delete Existing Elements [ ] Detailed Fillet Modeling [x] Display AutoGEM Messages [ ] Automatic Interrupt------------------------------------------
Shell Element Type: Quad and Tri Solid Element Type: Tetra
Allowable Angles (Degrees): Edge Min: 5.0 Max: 175.0 Face Min: 5.0 Max: 175.0
Max Allowable Edge Turn (Degrees): 95.0
Max Allowable Aspect Ratio: 30.0
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Working on 1 volume(s) ... Pre-processing features for 4 surfaces ... Searching for existing solid elements inside the volume ... Found 0 existing solid element(s) inside the volume. Pre-processing boundary features ... Optimizing boundary point locations ... Detecting thin features on the volume ... Pre-processing volume features ... Creating solid elements ...
58.8% complete after 2.0 min (4875 elements). 64.7% complete after 4.0 min (5694 elements).