2 thermal loads at the same time

- July 4, 2023 at 10:37 am
  
  Martin Hnilica
  Subscriber
  
  Hello, need an advice. I am trying to create thermal transient simulation (in future it will be coupled transient) with laser beam. For moving heat source I am using APDL, for simulation volumetric heat source command HGEN is used. Untill this point it works fine. Problem is, that it is dual laser beam welding, so I need to have 2 heat sources (2x APDL commands) moving in a row, in one load step on one solid. One of them is still ignored. It is possible to in ANSYS workbench R1 set up simulation, that cointains two heat sources for one solid in one load step? And if so, how?
  
  Thanks in advance
- July 6, 2023 at 12:46 pm
  
  Ashish Khemka
  Forum Moderator
  
  Hi,
  Please see if this link helps: Is it possible to define multiple load (Heat generation rate) in table type array parameter using a *DO loop? - Ansys Knowledge
  Regards,
  Ashish Khemka
- July 7, 2023 at 8:26 am
  
  Martin Hnilica
  Subscriber
  
  Thanks for response, but it seems like this is not right solution for me. I do not want to create a loop where one laser beam will leave and another one will show on, but two heat sources close behind. Is there any option how to not ignore second set of commands? Or some way to change substitute choice of commands to some kind of additive choice?
- July 11, 2023 at 9:54 am
  
  Martin Hnilica
  Subscriber
  
  UP, Still looking for solution
- July 12, 2023 at 3:21 pm
  
  wrbulat
  Ansys Employee
  
  Hi Martin,
  Sorry, your objective is not perfectly clear to me. It sounds like you want the apply the energy of two separate laser beams in the same location as they move along the surface. I would think the heat from a laser beam should be applied as a surface heat flux (SF,,HFLUX), rather than as a volumetrically distributed heat density (BF,,HGEN).
  Until we get clear on that, I can say that two things come to my mind that might help you. The first one is only applicable to the application of surface heat flux. You can create duplicate thermal surface effect elements (SURF152) on the heated surfaces with the ESURF command, and apply the heat attributable to each laser to each individual copy of the surface effect elements.
  The second thought is to use either the BFCUM (for volumetric loads) or SFCUM (for surface loads) commands. These allow subsequently specified loads to accumulate... to be added to previously applied loads (rather than replacing them, which is the default behavior):
  I hope this helps.
  Bill
- July 13, 2023 at 1:47 pm
  
  Martin Hnilica
  Subscriber
  
  Hello Bill, to explain my problem. I am trying to create dual beam laser welding - in dual laser beam welding laser beams go in a row. I attached a schematics how it is works:
  I already created surface model with usage of HFLUX, but I got feedback, that it got some drawbacks, which does not represent reality and I should try volumetric heat source. That BFCUM command sounds promising and that is probably, that for what i am looking for. My way of solving this problem was to create 2 separate APDL commands (shown below)
  
  Commands was based as tangent to the circle with extra depth in Z axis and movement of the beam is done as function of time moving along Y axis.
  .
  I also have created second set of beam parameters same way, to have possibility to operate them separately. They work fine 1 by 1, but not together. For that BFCUM command you recommend to put those commands in one commands list, or how to make it work?
  
  Thanks
  
  Martin