Thermal and dissipative effects accompanying Lüders band propagation

This study deals with an experimental investigation of thermal and calorimetric effects induced by Lüders band propagation during monotonic and quasi-static tensile tests. One grade of steel is considered. Temperature variations were measured with an infrared camera on the surface of flat samples. Heat sources were deduced from thermal data using the local heat diffusion equation. For elastoplastic materials, when no phase transition occurs, the heat source is essentially due to intrinsic dissipation. The experiments revealed that a dissipation wave accompanied Lüders band propagation. Some characteristics of the wave, such as its shape, orientation and velocity, were derived from the experimental measurements and compared to previously published results. Finally, comparison of the calorimetric and kinematic data revealed a dissipation function proportional to the absolute value of the longitudinal plastic strain rate.