Electrothermics

5.10. Difficulty of the electrothermal coupling

Due to the variation of the physical properties as a function of the temperature and the coupling between the electromagnetic and thermal equations, a strong coupling algorithm was shown in Figure 5.76. For each timestep, this algorithm requires multiple resolutions of the thermal and magnetodynamic equations. Solving the thermal equations takes a few seconds, but this is not the case for the magnetodynamic formulation, which requires a computation time of about an hour.

For a strong coupling, the electromagnetic problem is likely to be solved hundreds of times, which leads to a computation time of a few days. This computation time is of course prohibitive, especially in the development phase of a process. If this resolution could be done a reduced number of times, the time gain would be considerable. It then becomes interesting to study the sensitivity of the power induced in a composite as a function of carbon’s electrical conductivity.

5.10.1. Study of the sensitivity of the induced power’s variation as a function of the temperature

The studied composite has a TP PEEK matrix, which has a melting point of 340°C. Since we know that the conductivity of carbon increases by 0.05% by degree, the increase in conductivity is 8% for a composite going from 20°C to 180°C and 17% for a composite going up to 340°C. For an inductive current of 265 A and a temperature of 20°C, the induced power is 397 W in a 16-fold composite. It goes to 413 ...