A chemo-mechano-thermodynamical contact theory for adhesion, friction and (de)bonding reactions

TL;DR

This paper develops a comprehensive continuum model for coupled chemical, mechanical, and thermal contact interactions, integrating thermodynamics and providing analytical test cases for validation.

Contribution

It introduces a general, thermodynamically consistent contact formulation that includes chemical bonding, thermal effects, and their coupling, extending existing models with rigorous derivation from fundamental principles.

Findings

The formulation captures exothermic and endothermic chemical reactions at contact.

It distinguishes between long-range and short-range surface interactions.

Three analytical test cases demonstrate the model's capability for verifying computational simulations.

Abstract

This work presents a self-contained continuum formulation for coupled chemical, mechanical and thermal contact interactions. The formulation is very general and hence admits arbitrary geometry, deformation and material behavior. All model equations are derived rigorously from the balance laws of mass, momentum, energy and entropy in the framework of irreversible thermodynamics, thus exposing all the coupling present in the field equations and constitutive relations. In the process, the conjugated kinematic and kinetic variables for mechanical, thermal and chemical contact are identified, and the analogies between mechanical, thermal and chemical contact are highlighted. Particular focus is placed on the thermodynamics of chemical bonding distinguishing between exothermic and endothermic contact reactions. Distinction is also made between long-range, non-touching surface interactions and short-range, touching contact. For all constitutive relations examples are proposed and discussed comprehensively with particular focus on their coupling. Finally, three analytical test cases are presented that illustrate the thermo-chemo-mechanical contact coupling and are useful for verifying computational models. While the main novelty is the extension of existing contact formulations to chemical contact, the presented formulation also sheds new light on thermo-mechanical contact, since it is consistently derived from basic principles using only few assumptions.