This subnode should be used to model heat generation due to changes in stress, which may be important in small structures vibrating at high frequencies.

The Thermoelastic damping Qted should be specified either as a User defined value, or as the thermoelastic damping contribution straight from the solid mechanics interfaces, when you add a Thermal Expansion subnode (with the Structural Mechanics Module). In the latter case it is defined by

where S is the second Piola-Kirchhoff tensor and α is the coefficient of thermal expansion.

Physics Tab with Solid selected in the model tree:
Attributes>Thermoelastic Damping