Empathy List Archives

CA

Caba, Aaron (US)

Mon, Oct 31, 2022 7:16 PM

I have a transient thermal problem where two parts are bonded together with an adhesive. During the (one time) use, the bond line gets hot enough to char the adhesive and cause a change in the thermal conductance across the bond line. I'm using contact between the parts with a specified thermal conductance (TCC) instead of trying to explicitly model the adhesive. I have figured out how to make the Thermal Conductance Coefficient depend on the temperature at the interface with a command snip in the contact definition:

*dim,myTCC,Table,4,,,TEMP
*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C
myTCC(1,1)=800,800,50,50 ! TCC value
rmod, tid, 14,%myTCC%
rmod, cid, 14,%myTCC%

This works great as long as the temperature is monotonically increasing, but I also have experimental data through the cool-down phase that I want to match. Unfortunately, my APDL solution is reversible in temperature and the bond begins conducting again when the assembly starts to cool.

Does anyone have an idea how to permanently and irreversibly change the Thermal Conductance Coefficient of the contact as a function of temperature and/or temperature history?

Thanks!

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100
www.baesystems.com

I have a transient thermal problem where two parts are bonded together with an adhesive. During the (one time) use, the bond line gets hot enough to char the adhesive and cause a change in the thermal conductance across the bond line. I'm using contact between the parts with a specified thermal conductance (TCC) instead of trying to explicitly model the adhesive. I have figured out how to make the Thermal Conductance Coefficient depend on the temperature at the interface with a command snip in the contact definition: *dim,myTCC,Table,4,,,TEMP *taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C myTCC(1,1)=800,800,50,50 ! TCC value rmod, tid, 14,%myTCC% rmod, cid, 14,%myTCC% This works great as long as the temperature is monotonically increasing, but I also have experimental data through the cool-down phase that I want to match. Unfortunately, my APDL solution is reversible in temperature and the bond begins conducting again when the assembly starts to cool. Does anyone have an idea how to permanently and irreversibly change the Thermal Conductance Coefficient of the contact as a function of temperature and/or temperature history? Thanks! Aaron C. Caba, Ph.D. Sr. Principal R&D Engineer II BAE Systems, Inc. | Ordnance Systems, Inc. E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100 www.baesystems.com

T

Tom

Mon, Oct 31, 2022 7:28 PM

Aaron,

Does skill work in a thermal simulation? If so, you could create two different contact pairs: one for heating, and one for cooling. You should be able to then check during the solution for the target temperature and use ealive and ekill. The downside is the increased solution time.

Just a thought.

Best Regards,
Tom caltabellotta
SeniorMechanical Engineer
CACI INC.

Sent from my iPhone

On Oct 31, 2022, at 3:16 PM, Caba, Aaron (US) via Xansys xansys-temp@list.xansys.org wrote:

I have a transient thermal problem where two parts are bonded together with an adhesive. During the (one time) use, the bond line gets hot enough to char the adhesive and cause a change in the thermal conductance across the bond line. I'm using contact between the parts with a specified thermal conductance (TCC) instead of trying to explicitly model the adhesive. I have figured out how to make the Thermal Conductance Coefficient depend on the temperature at the interface with a command snip in the contact definition:

*dim,myTCC,Table,4,,,TEMP
*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C
myTCC(1,1)=800,800,50,50 ! TCC value
rmod, tid, 14,%myTCC%
rmod, cid, 14,%myTCC%

This works great as long as the temperature is monotonically increasing, but I also have experimental data through the cool-down phase that I want to match. Unfortunately, my APDL solution is reversible in temperature and the bond begins conducting again when the assembly starts to cool.

Does anyone have an idea how to permanently and irreversibly change the Thermal Conductance Coefficient of the contact as a function of temperature and/or temperature history?

Thanks!

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100
www.baesystems.com

Xansys mailing list -- xansys-temp@list.xansys.org
To unsubscribe send an email to xansys-temp-leave@list.xansys.org
If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day.

Please send administrative requests such as deletion from XANSYS to xansys-mod@tynecomp.co.uk and not to the list

Aaron, Does skill work in a thermal simulation? If so, you could create two different contact pairs: one for heating, and one for cooling. You should be able to then check during the solution for the target temperature and use ealive and ekill. The downside is the increased solution time. Just a thought. Best Regards, Tom caltabellotta SeniorMechanical Engineer CACI INC. Sent from my iPhone On Oct 31, 2022, at 3:16 PM, Caba, Aaron (US) via Xansys <xansys-temp@list.xansys.org> wrote: I have a transient thermal problem where two parts are bonded together with an adhesive. During the (one time) use, the bond line gets hot enough to char the adhesive and cause a change in the thermal conductance across the bond line. I'm using contact between the parts with a specified thermal conductance (TCC) instead of trying to explicitly model the adhesive. I have figured out how to make the Thermal Conductance Coefficient depend on the temperature at the interface with a command snip in the contact definition: *dim,myTCC,Table,4,,,TEMP *taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C myTCC(1,1)=800,800,50,50 ! TCC value rmod, tid, 14,%myTCC% rmod, cid, 14,%myTCC% This works great as long as the temperature is monotonically increasing, but I also have experimental data through the cool-down phase that I want to match. Unfortunately, my APDL solution is reversible in temperature and the bond begins conducting again when the assembly starts to cool. Does anyone have an idea how to permanently and irreversibly change the Thermal Conductance Coefficient of the contact as a function of temperature and/or temperature history? Thanks! Aaron C. Caba, Ph.D. Sr. Principal R&D Engineer II BAE Systems, Inc. | Ordnance Systems, Inc. E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100 www.baesystems.com _______________________________________________ Xansys mailing list -- xansys-temp@list.xansys.org To unsubscribe send an email to xansys-temp-leave@list.xansys.org If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day. Please send administrative requests such as deletion from XANSYS to xansys-mod@tynecomp.co.uk and not to the list

SI

Slater, Irene (Irene)

Mon, Oct 31, 2022 7:36 PM

Aaron,

Another thought, one you may not like, is to do the thermal-mechanical coupled simulation and allow the contact to open up as needed during the cool-down step as you say it does. This will increase solution time too! You will have the time history of the opening/closing.

Regards,
Irene Slater
Corning Incorporated

-----Original Message-----
From: Tom cameljoe@optonline.net
Sent: Monday, October 31, 2022 3:29 PM
To: XANSYS Mailing List Home xansys-temp@list.xansys.org
Cc: Caba, Aaron (US) Aaron.Caba@baesystems.com
Subject: [EXTERNAL]--[Xansys] Re: [APDL] Permanently change bond's thermal conductance

Aaron,

Does skill work in a thermal simulation? If so, you could create two different contact pairs: one for heating, and one for cooling. You should be able to then check during the solution for the target temperature and use ealive and ekill. The downside is the increased solution time.

Just a thought.

Best Regards,
Tom caltabellotta
SeniorMechanical Engineer
CACI INC.

Sent from my iPhone

On Oct 31, 2022, at 3:16 PM, Caba, Aaron (US) via Xansys xansys-temp@list.xansys.org wrote:

I have a transient thermal problem where two parts are bonded together with an adhesive. During the (one time) use, the bond line gets hot enough to char the adhesive and cause a change in the thermal conductance across the bond line. I'm using contact between the parts with a specified thermal conductance (TCC) instead of trying to explicitly model the adhesive. I have figured out how to make the Thermal Conductance Coefficient depend on the temperature at the interface with a command snip in the contact definition:

*dim,myTCC,Table,4,,,TEMP
*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C
myTCC(1,1)=800,800,50,50 ! TCC value
rmod, tid, 14,%myTCC%
rmod, cid, 14,%myTCC%

This works great as long as the temperature is monotonically increasing, but I also have experimental data through the cool-down phase that I want to match. Unfortunately, my APDL solution is reversible in temperature and the bond begins conducting again when the assembly starts to cool.

Does anyone have an idea how to permanently and irreversibly change the Thermal Conductance Coefficient of the contact as a function of temperature and/or temperature history?

Thanks!

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100 www.baesystems.com _______________________________________________
Xansys mailing list -- xansys-temp@list.xansys.org To unsubscribe send an email to xansys-temp-leave@list.xansys.org If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day.

Please send administrative requests such as deletion from XANSYS to xansys-mod@tynecomp.co.uk and not to the list _______________________________________________
Xansys mailing list -- xansys-temp@list.xansys.org To unsubscribe send an email to xansys-temp-leave@list.xansys.org If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day.

Please send administrative requests such as deletion from XANSYS to xansys-mod@tynecomp.co.uk and not to the list

Aaron, Another thought, one you may not like, is to do the thermal-mechanical coupled simulation and allow the contact to open up as needed during the cool-down step as you say it does. This will increase solution time too! You will have the time history of the opening/closing. Regards, Irene Slater Corning Incorporated -----Original Message----- From: Tom <cameljoe@optonline.net> Sent: Monday, October 31, 2022 3:29 PM To: XANSYS Mailing List Home <xansys-temp@list.xansys.org> Cc: Caba, Aaron (US) <Aaron.Caba@baesystems.com> Subject: [EXTERNAL]--[Xansys] Re: [APDL] Permanently change bond's thermal conductance Aaron, Does skill work in a thermal simulation? If so, you could create two different contact pairs: one for heating, and one for cooling. You should be able to then check during the solution for the target temperature and use ealive and ekill. The downside is the increased solution time. Just a thought. Best Regards, Tom caltabellotta SeniorMechanical Engineer CACI INC. Sent from my iPhone On Oct 31, 2022, at 3:16 PM, Caba, Aaron (US) via Xansys <xansys-temp@list.xansys.org> wrote: I have a transient thermal problem where two parts are bonded together with an adhesive. During the (one time) use, the bond line gets hot enough to char the adhesive and cause a change in the thermal conductance across the bond line. I'm using contact between the parts with a specified thermal conductance (TCC) instead of trying to explicitly model the adhesive. I have figured out how to make the Thermal Conductance Coefficient depend on the temperature at the interface with a command snip in the contact definition: *dim,myTCC,Table,4,,,TEMP *taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C myTCC(1,1)=800,800,50,50 ! TCC value rmod, tid, 14,%myTCC% rmod, cid, 14,%myTCC% This works great as long as the temperature is monotonically increasing, but I also have experimental data through the cool-down phase that I want to match. Unfortunately, my APDL solution is reversible in temperature and the bond begins conducting again when the assembly starts to cool. Does anyone have an idea how to permanently and irreversibly change the Thermal Conductance Coefficient of the contact as a function of temperature and/or temperature history? Thanks! Aaron C. Caba, Ph.D. Sr. Principal R&D Engineer II BAE Systems, Inc. | Ordnance Systems, Inc. E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100 www.baesystems.com _______________________________________________ Xansys mailing list -- xansys-temp@list.xansys.org To unsubscribe send an email to xansys-temp-leave@list.xansys.org If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day. Please send administrative requests such as deletion from XANSYS to xansys-mod@tynecomp.co.uk and not to the list _______________________________________________ Xansys mailing list -- xansys-temp@list.xansys.org To unsubscribe send an email to xansys-temp-leave@list.xansys.org If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day. Please send administrative requests such as deletion from XANSYS to xansys-mod@tynecomp.co.uk and not to the list

MG

Mohammad Gharaibeh

Mon, Oct 31, 2022 8:29 PM

A quick thought:

Can’t you use submodeling? The global model is the model with temperature
rise. The local model is for cooling down stage. You can define TCC as
function of temperature in the local model but in reverse scheme, in a
similar fashion of what have you provided.

Hope this works!

Best,
Mohammad

On Monday, October 31, 2022, Caba, Aaron (US) via Xansys <
xansys-temp@list.xansys.org> wrote:

I have a transient thermal problem where two parts are bonded together
with an adhesive. During the (one time) use, the bond line gets hot enough
to char the adhesive and cause a change in the thermal conductance across
the bond line. I'm using contact between the parts with a specified
thermal conductance (TCC) instead of trying to explicitly model the
adhesive. I have figured out how to make the Thermal Conductance
Coefficient depend on the temperature at the interface with a command snip
in the contact definition:

*dim,myTCC,Table,4,,,TEMP
*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C
myTCC(1,1)=800,800,50,50 ! TCC value
rmod, tid, 14,%myTCC%
rmod, cid, 14,%myTCC%

This works great as long as the temperature is monotonically increasing,
but I also have experimental data through the cool-down phase that I want
to match. Unfortunately, my APDL solution is reversible in temperature and
the bond begins conducting again when the assembly starts to cool.

Does anyone have an idea how to permanently and irreversibly change the
Thermal Conductance Coefficient of the contact as a function of temperature
and/or temperature history?

Thanks!

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road,
Radford VA 24143-0100
www.baesystems.com

Xansys mailing list -- xansys-temp@list.xansys.org
To unsubscribe send an email to xansys-temp-leave@list.xansys.org
If you are receiving too many emails from XANSYS please consider changing
account settings to Digest mode which will send a single email per day.

Please send administrative requests such as deletion from XANSYS to
xansys-mod@tynecomp.co.uk and not to the list

--

---====
Mohammad A Gharaibeh, Ph.D.
Associate Professor
Department of Mechanical Engineering
The Hashemite University
P.O. Box 330127
Zarqa, 13133, Jordan
Tel: +962 - 5 - 390 3333 Ext. 4771
Fax: +962 - 5 - 382 6348

---====

A quick thought: Can’t you use submodeling? The global model is the model with temperature rise. The local model is for cooling down stage. You can define TCC as function of temperature in the local model but in reverse scheme, in a similar fashion of what have you provided. Hope this works! Best, Mohammad On Monday, October 31, 2022, Caba, Aaron (US) via Xansys < xansys-temp@list.xansys.org> wrote: > I have a transient thermal problem where two parts are bonded together > with an adhesive. During the (one time) use, the bond line gets hot enough > to char the adhesive and cause a change in the thermal conductance across > the bond line. I'm using contact between the parts with a specified > thermal conductance (TCC) instead of trying to explicitly model the > adhesive. I have figured out how to make the Thermal Conductance > Coefficient depend on the temperature at the interface with a command snip > in the contact definition: > > *dim,myTCC,Table,4,,,TEMP > *taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C > myTCC(1,1)=800,800,50,50 ! TCC value > rmod, tid, 14,%myTCC% > rmod, cid, 14,%myTCC% > > This works great as long as the temperature is monotonically increasing, > but I also have experimental data through the cool-down phase that I want > to match. Unfortunately, my APDL solution is reversible in temperature and > the bond begins conducting again when the assembly starts to cool. > > Does anyone have an idea how to permanently and irreversibly change the > Thermal Conductance Coefficient of the contact as a function of temperature > and/or temperature history? > > Thanks! > > Aaron C. Caba, Ph.D. > Sr. Principal R&D Engineer II > BAE Systems, Inc. | Ordnance Systems, Inc. > > E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, > Radford VA 24143-0100 > www.baesystems.com > _______________________________________________ > Xansys mailing list -- xansys-temp@list.xansys.org > To unsubscribe send an email to xansys-temp-leave@list.xansys.org > If you are receiving too many emails from XANSYS please consider changing > account settings to Digest mode which will send a single email per day. > > Please send administrative requests such as deletion from XANSYS to > xansys-mod@tynecomp.co.uk and not to the list > -- ===================================== Mohammad A Gharaibeh, Ph.D. Associate Professor Department of Mechanical Engineering The Hashemite University P.O. Box 330127 Zarqa, 13133, Jordan Tel: +962 - 5 - 390 3333 Ext. 4771 Fax: +962 - 5 - 382 6348 =====================================

KD

Keith DiRienz

Tue, Nov 1, 2022 4:44 AM

Aaron,
You can create a new material number that has the TCC of the charred
elements and then use the MPCHG command to change the material number
of the charred elements during solution before you begin the cool down cycle.
Keith DiRienz
FEA Technologies
Dana Point, CA

At 12:16 PM 10/31/2022, you wrote:

I have a transient thermal problem where two parts are bonded
together with an adhesive. During the (one time) use, the bond line
gets hot enough to char the adhesive and cause a change in the
thermal conductance across the bond line. I'm using contact between
the parts with a specified thermal conductance (TCC) instead of
trying to explicitly model the adhesive. I have figured out how to
make the Thermal Conductance Coefficient depend on the temperature
at the interface with a command snip in the contact definition:

*dim,myTCC,Table,4,,,TEMP
*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C
myTCC(1,1)=800,800,50,50 ! TCC value
rmod, tid, 14,%myTCC%
rmod, cid, 14,%myTCC%

This works great as long as the temperature is monotonically
increasing, but I also have experimental data through the cool-down
phase that I want to match. Unfortunately, my APDL solution is
reversible in temperature and the bond begins conducting again when
the assembly starts to cool.

Does anyone have an idea how to permanently and irreversibly change
the Thermal Conductance Coefficient of the contact as a function of
temperature and/or temperature history?

Thanks!

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

Keith DiRienz, P.E.
FEA Technologies
Office: 949.481.4946
Cell: 949-910-7049 (New !)

Aaron, You can create a new material number that has the TCC of the charred elements and then use the MPCHG command to change the material number of the charred elements during solution before you begin the cool down cycle. Keith DiRienz FEA Technologies Dana Point, CA At 12:16 PM 10/31/2022, you wrote: >I have a transient thermal problem where two parts are bonded >together with an adhesive. During the (one time) use, the bond line >gets hot enough to char the adhesive and cause a change in the >thermal conductance across the bond line. I'm using contact between >the parts with a specified thermal conductance (TCC) instead of >trying to explicitly model the adhesive. I have figured out how to >make the Thermal Conductance Coefficient depend on the temperature >at the interface with a command snip in the contact definition: > >*dim,myTCC,Table,4,,,TEMP >*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C >myTCC(1,1)=800,800,50,50 ! TCC value >rmod, tid, 14,%myTCC% >rmod, cid, 14,%myTCC% > >This works great as long as the temperature is monotonically >increasing, but I also have experimental data through the cool-down >phase that I want to match. Unfortunately, my APDL solution is >reversible in temperature and the bond begins conducting again when >the assembly starts to cool. > >Does anyone have an idea how to permanently and irreversibly change >the Thermal Conductance Coefficient of the contact as a function of >temperature and/or temperature history? > >Thanks! > >Aaron C. Caba, Ph.D. >Sr. Principal R&D Engineer II >BAE Systems, Inc. | Ordnance Systems, Inc. Keith DiRienz, P.E. FEA Technologies Office: 949.481.4946 Cell: 949-910-7049 (New !)

CA

Caba, Aaron (US)

Fri, Nov 4, 2022 4:04 PM

Keith, Irene, Tom, Harish:

Thank you for the ideas. The most elegant way to fix this would be to write a UPF USERCNPROP.F that degrades the TCC with rising temperature. Since I don't currently possess the Intel compiler, that is not an option.

I ended up creating two co-located contact surfaces with different TCC defined, then hacked together an APDL macro that checks the temperatures and EKILL the virgin element and EALIVE the charred element. Then I subdivide into many steps and run the macro after each.

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

Office: +1 540 639 7086 | Mobile: +1 540 230 3906 | E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100
www.baesystems.com

At 12:16 PM 10/31/2022, you wrote:

I have a transient thermal problem where two parts are bonded together
with an adhesive. During the (one time) use, the bond line gets hot
enough to char the adhesive and cause a change in the thermal
conductance across the bond line. I'm using contact between the parts
with a specified thermal conductance (TCC) instead of trying to
explicitly model the adhesive. I have figured out how to make the
Thermal Conductance Coefficient depend on the temperature at the
interface with a command snip in the contact definition:

*dim,myTCC,Table,4,,,TEMP
*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C
myTCC(1,1)=800,800,50,50 ! TCC value
rmod, tid, 14,%myTCC%
rmod, cid, 14,%myTCC%

This works great as long as the temperature is monotonically
increasing, but I also have experimental data through the cool-down
phase that I want to match. Unfortunately, my APDL solution is
reversible in temperature and the bond begins conducting again when the
assembly starts to cool.

Does anyone have an idea how to permanently and irreversibly change the
Thermal Conductance Coefficient of the contact as a function of
temperature and/or temperature history?

Thanks!

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

Keith, Irene, Tom, Harish: Thank you for the ideas. The most elegant way to fix this would be to write a UPF USERCNPROP.F that degrades the TCC with rising temperature. Since I don't currently possess the Intel compiler, that is not an option. I ended up creating two co-located contact surfaces with different TCC defined, then hacked together an APDL macro that checks the temperatures and EKILL the virgin element and EALIVE the charred element. Then I subdivide into many steps and run the macro after each. Aaron C. Caba, Ph.D. Sr. Principal R&D Engineer II BAE Systems, Inc. | Ordnance Systems, Inc. Office: +1 540 639 7086 | Mobile: +1 540 230 3906 | E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100 www.baesystems.com At 12:16 PM 10/31/2022, you wrote: >I have a transient thermal problem where two parts are bonded together >with an adhesive. During the (one time) use, the bond line gets hot >enough to char the adhesive and cause a change in the thermal >conductance across the bond line. I'm using contact between the parts >with a specified thermal conductance (TCC) instead of trying to >explicitly model the adhesive. I have figured out how to make the >Thermal Conductance Coefficient depend on the temperature at the >interface with a command snip in the contact definition: > >*dim,myTCC,Table,4,,,TEMP >*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C >myTCC(1,1)=800,800,50,50 ! TCC value >rmod, tid, 14,%myTCC% >rmod, cid, 14,%myTCC% > >This works great as long as the temperature is monotonically >increasing, but I also have experimental data through the cool-down >phase that I want to match. Unfortunately, my APDL solution is >reversible in temperature and the bond begins conducting again when the >assembly starts to cool. > >Does anyone have an idea how to permanently and irreversibly change the >Thermal Conductance Coefficient of the contact as a function of >temperature and/or temperature history? > >Thanks! > >Aaron C. Caba, Ph.D. >Sr. Principal R&D Engineer II >BAE Systems, Inc. | Ordnance Systems, Inc.

T

Tom

Fri, Nov 4, 2022 4:41 PM

Aaron,

Thank-you for the update!

Best regards,
Tom Caltabellotta
Senior Mechanical Engineer
CACI Inc

Sent from my iPhone

On Nov 4, 2022, at 12:04 PM, Caba, Aaron (US) via Xansys xansys-temp@list.xansys.org wrote:

Keith, Irene, Tom, Harish:

Thank you for the ideas. The most elegant way to fix this would be to write a UPF USERCNPROP.F that degrades the TCC with rising temperature. Since I don't currently possess the Intel compiler, that is not an option.

I ended up creating two co-located contact surfaces with different TCC defined, then hacked together an APDL macro that checks the temperatures and EKILL the virgin element and EALIVE the charred element. Then I subdivide into many steps and run the macro after each.

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

Office: +1 540 639 7086 | Mobile: +1 540 230 3906 | E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100
www.baesystems.com

At 12:16 PM 10/31/2022, you wrote:

I have a transient thermal problem where two parts are bonded together
with an adhesive. During the (one time) use, the bond line gets hot
enough to char the adhesive and cause a change in the thermal
conductance across the bond line. I'm using contact between the parts
with a specified thermal conductance (TCC) instead of trying to
explicitly model the adhesive. I have figured out how to make the
Thermal Conductance Coefficient depend on the temperature at the
interface with a command snip in the contact definition:

*dim,myTCC,Table,4,,,TEMP
*taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C
myTCC(1,1)=800,800,50,50 ! TCC value
rmod, tid, 14,%myTCC%
rmod, cid, 14,%myTCC%

This works great as long as the temperature is monotonically
increasing, but I also have experimental data through the cool-down
phase that I want to match. Unfortunately, my APDL solution is
reversible in temperature and the bond begins conducting again when the
assembly starts to cool.

Does anyone have an idea how to permanently and irreversibly change the
Thermal Conductance Coefficient of the contact as a function of
temperature and/or temperature history?

Thanks!

Aaron C. Caba, Ph.D.
Sr. Principal R&D Engineer II
BAE Systems, Inc. | Ordnance Systems, Inc.

Xansys mailing list -- xansys-temp@list.xansys.org
To unsubscribe send an email to xansys-temp-leave@list.xansys.org
If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day.

Please send administrative requests such as deletion from XANSYS to xansys-mod@tynecomp.co.uk and not to the list

Aaron, Thank-you for the update! Best regards, Tom Caltabellotta Senior Mechanical Engineer CACI Inc Sent from my iPhone On Nov 4, 2022, at 12:04 PM, Caba, Aaron (US) via Xansys <xansys-temp@list.xansys.org> wrote: Keith, Irene, Tom, Harish: Thank you for the ideas. The most elegant way to fix this would be to write a UPF USERCNPROP.F that degrades the TCC with rising temperature. Since I don't currently possess the Intel compiler, that is not an option. I ended up creating two co-located contact surfaces with different TCC defined, then hacked together an APDL macro that checks the temperatures and EKILL the virgin element and EALIVE the charred element. Then I subdivide into many steps and run the macro after each. Aaron C. Caba, Ph.D. Sr. Principal R&D Engineer II BAE Systems, Inc. | Ordnance Systems, Inc. Office: +1 540 639 7086 | Mobile: +1 540 230 3906 | E-mail: aaron.caba@baesystems.com | Mail: 4050 Peppers Ferry Road, Radford VA 24143-0100 www.baesystems.com At 12:16 PM 10/31/2022, you wrote: > I have a transient thermal problem where two parts are bonded together > with an adhesive. During the (one time) use, the bond line gets hot > enough to char the adhesive and cause a change in the thermal > conductance across the bond line. I'm using contact between the parts > with a specified thermal conductance (TCC) instead of trying to > explicitly model the adhesive. I have figured out how to make the > Thermal Conductance Coefficient depend on the temperature at the > interface with a command snip in the contact definition: > > *dim,myTCC,Table,4,,,TEMP > *taxis,myTCC(1),1,0,200,220,2000 ! Temperature in C > myTCC(1,1)=800,800,50,50 ! TCC value > rmod, tid, 14,%myTCC% > rmod, cid, 14,%myTCC% > > This works great as long as the temperature is monotonically > increasing, but I also have experimental data through the cool-down > phase that I want to match. Unfortunately, my APDL solution is > reversible in temperature and the bond begins conducting again when the > assembly starts to cool. > > Does anyone have an idea how to permanently and irreversibly change the > Thermal Conductance Coefficient of the contact as a function of > temperature and/or temperature history? > > Thanks! > > Aaron C. Caba, Ph.D. > Sr. Principal R&D Engineer II > BAE Systems, Inc. | Ordnance Systems, Inc. _______________________________________________ Xansys mailing list -- xansys-temp@list.xansys.org To unsubscribe send an email to xansys-temp-leave@list.xansys.org If you are receiving too many emails from XANSYS please consider changing account settings to Digest mode which will send a single email per day. Please send administrative requests such as deletion from XANSYS to xansys-mod@tynecomp.co.uk and not to the list