Infrared thermography was used to study the thermal signature of a rubber-like granular material subjected to cyclic confined compression. The discrete medium consisted of cylinders placed in parallel. A fluctuation of the temperature at the same frequency as the mechanical loading was observed, as well as a global self-heating as the cycles progressed. This can be associated with the thermoelastic coupling effect and the mechanical dissipation effect, respectively. The thermoelastic coupling effect is visible in all contact zones between the particles, which can be explained by the stress concentrations that occur there. A strong mechanical dissipation effect occurs at specific contacts, which can be explained by the high friction between certain particles.

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