Speaker
Description
This presentation introduces a thermodynamically consistent formulation for the heat source arising from plastic deformation within a small deformation framework (cf., [1,2]), which leads to an additive decomposition of the flow stress into two distinct parts: one associated with dissipation and another linked to the energy stored within the material due to microstructural changes, such as dislocation evolution and interaction. This provides a framework for investigating the thermomechanical coupling during plastic deformation. The consequences of the underlying assumptions for the dependence of the material functions and the free energy function are discussed.
The proposed decomposition provides a structured approach to understanding energy and stress partitioning during plastic deformation of metallic materials. Although established in a small deformation setting, the framework and its implications can be generalized to large deformations and may serve as a starting point for more refined studies of dislocation-based thermoplasticity in mono- and polycrystals. By focusing on the thermodynamic consistency of the formulation, this work contributes to the fundamental understanding of plastic deformation and lays the fundamentals for further exploration of the interplay between thermomechanical and microstructural effects. Selected experimental results based on in-situ infrared thermography measurements [3] during tensile tests and micromechanical model cases are discussed. Limitations and prospect for generalization are highlighted in the presentation.
[1] Bertram, A., \& Krawietz, A. (2012). On the introduction of thermoplasticity. Acta Mechanica, 223, 2257-2268.
[2] Rosakis, P., Rosakis, A. J., Ravichandran, G., \& Hodowany, J. (2000). A thermodynamic internal variable model for the partition of plastic work into heat and stored energy in metals. Journal of the Mechanics and Physics of Solids, 48(3), 581-607.
[3] Chrysochoos, A., \& Louche, H. (2000). An infrared image processing to analyse the calorific effects accompanying strain localisation. International journal of engineering science, 38(16), 1759-1788.
