Calculate Tension from known rolling setup

[ChRen95]

So, in recent times and to be honest also before we often got the question to include tension calculations.
Meaning, we should include the difference in speeds and the reaction of the rolling train.
So I created a first algorithm for that.
The idea and now also the implementation came from rolling sequence were the speeds were changed on purpose to create tension.
The resulting r-factors (often called reduction factors but actually those are speed ratios to my knowledge) were provided.
The implemented algorithm works using the premise, that the material only deforms elastically between the stands.
This condition yields, that the tensions can further be calculated using following equation:

$$ \sigma_{f} = E \cdot \epsilon = E \cdot \left( \frac{v_1 - v_0}{v_0} \right) $$

Since it's hard to find measured values we would be happy if someone has something and can provide us with a valid example.
The new solve method is called solve_interstand_tensions_with_given_velocity_ratios and will be available with the next update.

[QiangF]

Maybe we can relate this to the Torque change due to tension caused by the speed adjustment. Torque and speed is easier to measure.

[ChRen95]

Sure, that would be handled by the respective plugins like pyroll-lippmann-mahrenholz-force-torque and should work out of the box. Also, using the plugin pyroll-tension-spreading-interaction we would have the influence for the material flow included.

[sag-kalibreur]

Good idea from @QiangF. Torque and speed are available for comparison in the production process. If this can be implemented using the existing plugins pyroll-lippmann-mahrenholz-force-torque and pyroll-tension-spreading-interaction, so much the better! The solution should be to determine the tension between the stands at specified speeds.