Divergence because of temperature dependent material properties

[siggi84]

I am having a problem with temperature dependent material properties. I am doing thermal-electric analysis in 3D and I am using the solid69 element. The structure is made of silicon, silicon dioxide and platinum. On top of a thin silicon dioxide layer I have a nanowire which is heated resistively (by applying a voltage we get power dissipation P=I*V). Under the thin silicon dioxide layer I have thick layer of silicon.

Everything works fine when the resistivity of platinum is fixed (MP,RSVX,1,PtR_300) and I get a solution in ~1 minute. But when I make the resistivity temperature dependent
MPTEMP,1,300,1000
MPDATA,RSVX,1,1,PtR_300,PtR_1000
it seems like it doesn't converge at all. I usually use the AMG solver, but exactly the same thing happens when I use the sparse solver. What can I do to get convergence? Please help, I am getting desperate.

The resitivity variables are:
PtR_300 = 3.43e-13
PtR_1000 = 8.09E-13

The whole structure is defined in the attachment, and if you want to try it out you just have to comment/uncomment lines 217-219 properly.
Best regards,
Siggi84

 

[siggi84]

I have solved the problem. The trick was to enable line search:

SOLCONTROL,ON
LNSRCH,ON

best regards,
Siggi84