Volume/domain activation and deactivation, welding

shahpar73 · June 26, 2016, 09:03

Hi all
Is is possible to activate/deactivate (select/deselect) a particular portion of a volume or domain in CFX?
I want to simulate the weld pool shape after adding the filler metal and form a weld bead.
The volume/domain of the filler metal (shape of weld bead) is defined previously but is inactive and becomes active at the time when a heat source is applied.

ghorrocks · June 26, 2016, 20:54

What do you want to activate/deactivate? Can you post an image of what you want to model? I am well aware of how welding works, but please explain how you propose to model it.

shahpar73 · June 27, 2016, 10:24

The filler metal melts, drops down on the work piece and form a bead.
I want to model this phenomenon in CFX with a simple approach adapted by various researchers.
Researchers model the weld bead geometry (mesh elements) in advance and keep the selected elements inactive (using Kill command in ANSYS Mechanical) and make it active (using birth command) as soon as heat source is applied.
Inactive means not participating in calculations or elements/volumes with zero stiffness.
Some information are available on the link bellow but unfortunately not for CFX. Can we do similar in CFX?

http://www.mece.ualberta.ca/tutorial...irthDeath.html

To explain it more,
suppose there is a plate (of 50x50x6mm) with flat surface. As soon as I apply a heat source (say after 1s of the start of simulation), a hemisphere volume (8mm dia and 1mm height) appears on the flat surface which represents the addition of a filler metal drop. Now this hemisphere was there in the mesh but was inactive at the start of simulation and becomes active after 1s.

ghorrocks · June 27, 2016, 20:48

You cannot do cell birth and death in CFX. This sounds like a case for dynamic remeshing to me. Have a look at the ANSYS customer webpage for tutorial examples for this.

shahpar73 · June 28, 2016, 08:23

I appreciate your idea of dynamic re-meshing. It sounds applicable for the situation. Thanks for the help.

June 26, 2016, 09:03	Volume/domain activation and deactivation, welding	#1
shahpar73 Member Shahid Parvez Join Date: Jul 2009 Location: Pakistan Posts: 38 Rep Power: 17	Hi all Is is possible to activate/deactivate (select/deselect) a particular portion of a volume or domain in CFX? I want to simulate the weld pool shape after adding the filler metal and form a weld bead. The volume/domain of the filler metal (shape of weld bead) is defined previously but is inactive and becomes active at the time when a heat source is applied.

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June 26, 2016, 20:54		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,862 Rep Power: 144	What do you want to activate/deactivate? Can you post an image of what you want to model? I am well aware of how welding works, but please explain how you propose to model it.

June 27, 2016, 10:24		#3
shahpar73 Member Shahid Parvez Join Date: Jul 2009 Location: Pakistan Posts: 38 Rep Power: 17	The filler metal melts, drops down on the work piece and form a bead. I want to model this phenomenon in CFX with a simple approach adapted by various researchers. Researchers model the weld bead geometry (mesh elements) in advance and keep the selected elements inactive (using Kill command in ANSYS Mechanical) and make it active (using birth command) as soon as heat source is applied. Inactive means not participating in calculations or elements/volumes with zero stiffness. Some information are available on the link bellow but unfortunately not for CFX. Can we do similar in CFX? http://www.mece.ualberta.ca/tutorial...irthDeath.html To explain it more, suppose there is a plate (of 50x50x6mm) with flat surface. As soon as I apply a heat source (say after 1s of the start of simulation), a hemisphere volume (8mm dia and 1mm height) appears on the flat surface which represents the addition of a filler metal drop. Now this hemisphere was there in the mesh but was inactive at the start of simulation and becomes active after 1s.

June 27, 2016, 20:48		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,862 Rep Power: 144	You cannot do cell birth and death in CFX. This sounds like a case for dynamic remeshing to me. Have a look at the ANSYS customer webpage for tutorial examples for this.

June 28, 2016, 08:23		#5
shahpar73 Member Shahid Parvez Join Date: Jul 2009 Location: Pakistan Posts: 38 Rep Power: 17	I appreciate your idea of dynamic re-meshing. It sounds applicable for the situation. Thanks for the help.