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[THERM] Contact Conductance between solid and shell elements
 
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debabrata.podder
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Joined: 21 Feb 2013
Posts: 51
Location: NIT Meghalaya, India

PostPosted: Sat Jan 10, 2015 5:27 am  Reply with quote

Dear experts,
Iam using solid-shell model to simulate the thermal analysis. The elements used were solid70 and shell131. The materials were also same for solid and shell elements. While creating the thermal contact coupling, a value of thermal contact conductance was asked. If we provide a high value of thermal contact conductance (1e190), a discontinuity in thermal profile was obtained.
Can any body tell me what is the actual value of this thermal contact conductance between solid and shell elements?


Regards-
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Debabrata Podder(PhD)
Assistant Professor
NIT Meghalaya
India
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Martin Liddle
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Joined: 15 Aug 2008
Posts: 1274
Location: Chesterfield, UK

PostPosted: Sat Jan 10, 2015 5:52 am  Reply with quote

On 10/01/2015 12:27, debabrata.podder wrote
Quote:
Iam using solid-shell model to simulate the thermal analysis. The elements used were solid70 and shell131. The materials were also same for solid and shell elements. While creating the thermal contact coupling, a value of thermal contact conductance was asked. If we provide a high value of thermal contact conductance (1e190), a discontinuity in thermal profile was obtained.
Can any body tell me what is the actual value of this thermal contact conductance between solid and shell elements?
A value of 1E190 strikes me as excessively large but I don't know what
unit system you are using. A rule of thumb for approximating perfect
conductance is

TCC = KXX *10000 / ASMDIAG

where TCC is thermal contact conductance, KXX is the highest thermal
conductivity used in the model and ASMDIAG is the length of the diagonal
of a bounding box around the geometry; what value does this equation
give you?

Thermal contact conductance is really a way of introducing thermal
contact resistance (TCR) to the model and appropriates values of thermal
contact resistance can be found in the literature. The relationship is

TCC=1 /(TCR*A)

Where A is the interface area.


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Martin Liddle, Tynemouth Computer Services,
Chesterfield, Derbyshire, UK.
www.tynecomp.co.uk

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matt.sutton
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Joined: 21 Oct 2008
Posts: 134

PostPosted: Sat Jan 10, 2015 7:05 am  Reply with quote

Debabrata,
If you use keyopt(6)=1 for the shells you should be able to "paint" them onto the solids and thus eliminate the need to the contact elements. Your value of conductance looks way too high and appears to be an attempt to "eliminate" any contact resistance. I think the paint option is a better choice in that case.
Matt Sutton
www.padtinc.com


-----Original Message-----
From: Xansys [mailto:xansys-bounces@xansys.org] On Behalf Of debabrata.podder
Sent: Saturday, January 10, 2015 5:28 AM
To: xansys@xansys.org
Subject: [Xansys] [THERM] Contact Conductance between solid and shell elements

Dear experts,
Iam using solid-shell model to simulate the thermal analysis. The elements used were solid70 and shell131. The materials were also same for solid and shell elements. While creating the thermal contact coupling, a value of thermal contact conductance was asked. If we provide a high value of thermal contact conductance (1e190), a discontinuity in thermal profile was obtained.
Can any body tell me what is the actual value of this thermal contact conductance between solid and shell elements?


Regards-

------------------------
Debabrata Podder
Research Scholar
IIT Kharagpur
PIN NO.: 721302
India






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| Send administrative requests to xansys-mod@tynecomp.co.uk |
+-------------------------------------------------------------+
+-------------------------------------------------------------+
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| Hosted by PADT - www.padtinc.com |
| Send administrative requests to xansys-mod@tynecomp.co.uk |
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debabrata.podder
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Joined: 21 Feb 2013
Posts: 51
Location: NIT Meghalaya, India

PostPosted: Sat Jan 10, 2015 8:24 am  Reply with quote

Dear Matt Sutton,

Thank you very much for your suggestion.That paint option you told for shell element is working properly. Any option is there for coupling shell with solid for structural analysis
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Debabrata Podder(PhD)
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NIT Meghalaya
India
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matt.sutton
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Joined: 21 Oct 2008
Posts: 134

PostPosted: Sat Jan 10, 2015 9:07 am  Reply with quote

Debabrata,
You can try offsetting the shell node to the bottom surface of the shell with the secoffset command.
Matt Sutton
www.padtinc.com


-----Original Message-----
From: Xansys [mailto:xansys-bounces@xansys.org] On Behalf Of debabrata.podder
Sent: Saturday, January 10, 2015 8:24 AM
To: xansys@xansys.org
Subject: Re: [Xansys] [THERM] Contact Conductance between solid and shell elements

Dear Matt Sutton,

Thank you very much for your suggestion.That paint option you told for shell element is working properly. Any option is there for coupling shell with solid for structural analysis

------------------------
Debabrata Podder
Research Scholar
IIT Kharagpur
PIN NO.: 721302
India






+-------------------------------------------------------------+
| XANSYS web - www.xansys.org/forum |
| The Online Community for users of ANSYS, Inc. Software |
| Hosted by PADT - www.padtinc.com |
| Send administrative requests to xansys-mod@tynecomp.co.uk |
+-------------------------------------------------------------+
+-------------------------------------------------------------+
| XANSYS web - www.xansys.org/forum |
| The Online Community for users of ANSYS, Inc. Software |
| Hosted by PADT - www.padtinc.com |
| Send administrative requests to xansys-mod@tynecomp.co.uk |
+-------------------------------------------------------------+

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