Learning Forum

[k_ujjwal]

HI,

How to define thermal conductivity K(T(t)), which is a function of temperature 'T' at current simulation time 't' in APDL? Also, how to set the thermal conductivity of killed elements to negligible value?

I know, one way of doing it is by manually filling the table with temperature value and corresponding thermal conductivity. Is there a way of doing it automatically, where based on the current temperature value the thermal conductivity changes?

 I am trying to solve coupled problem (sturctural+thermal) in APDL. When plotting temp vs time plot in time-history postprocessor, the node shows a rise in temperature at the time when it is in killed state. I tried to further reduce the thermal conductivity value to 1e-30 by using 'ESTIF' command, but it's not working.

[dlooman]

The MPTEMP and MPDATA commands can be used to specify a temperature dependent thermal conductivity. ESTIF can be used to lower the thermal conductivity of dead elements. I would never specify such a small number as 1e-30 though. It could produce ill-conditioning. 1e-12 should be small enough. The temperature change in the dead elements may not be due to thermal conductivity. It may be necessary to constrain the nodes of dead elements to a temperature. (Only nodes that aren't shared with live elements.)