Application of FEM to coupled electric, thermal and mechanical problems

Two problems involving coupled electric and thermal fields are investigated by the finite element method. In a PTC thermistor the transient temperature field due to the losses is computed in each time step with the extremely non-linear dependence of conductivity on temperature taken into account. The mechanical stresses caused by the temperature gradient are hence obtained to facilitate the prediction of an eventual fracture of the PTC. In a second example the operation of a thermoelectric generator based on the Seebeck effect is simulated and its structure is optimized to attain maximal efficiency