Thanks Richard for your advices.

MoverZ,

You mean that stress analysis of heater coil (convection-external crossover-radiant) are usual in heater design; I was convinced that all this stuff is not useful due to the extreme flexibility of the coils so just a waste of time (in addition to all the other problems listed above).

Maybe I'm wrong, It's common to model in Caesar this part of the heater tubes?

What's the main intent of this kind of anlaysis?

TY.