Using IR Thermography to Analyze the Mechanical Response of a Granular Material

Abstract

The objective of the study is to analyze the thermomechanical response of a two-dimensional monodisperse granular system made of thermoplastic polyurethane (TPU) cylinders with elliptical cross-section. Cyclic confined compression tests were performed while an infrared (IR) camera measured the temperature changes at the surface of the cylinders. Thermoelastic coupling and mechanical dissipation were distinguished in the thermal evolution. The former was mainly evidenced as a consequence of stress concentrations in the interparticle contact zones. The latter was highlighted at specific contacts, which can be explained by strong friction in these zones. The higher the number of applied mechanical cycles, the higher the temperature rise as a consequence of an accumulation of heat due to mechanical dissipation production.