Inductive and Radiofrequency (RF) heating in LS-DYNA for medical and other industrial applications

Inductive and radiofrequency heating both rely on an electromagnetic power source to generate heat. However, they are based on different frequency scales that trigger different electromagnetic behavior and make some terms predominant over others. Inductive heating can be viewed as a “contactless” form of heating where a current source (typically a copper coil) with a frequency in the range of 𝐾𝐾𝐾𝐾𝐾𝐾 or MHz approaches another conductor thus triggering induced currents (Eddy currents) in nearby conductors which can generate heat, depending on the material’s properties (resistivity, permeability). In this paper, radiofrequency heating can be viewed as an extension of traditional Resistive heating where an electrode is plugged between two ends of a specific material. Contrary to resistive heating, the material’s electrical conductivity is usually very low, or the material can be an insulator, but the input source is in a high frequency range (𝐺𝐺𝐾𝐾𝐾𝐾 or higher) which triggers molecular displacements that generate heat via friction. This dielectric heat source term becomes the dominant factor rather than the Ohmic losses term.