Numerical modelling of thermomechanical solids with highly-conductive energetic interfaces

Interfaces within a solid can play a significant role in the overall response of a body. The influence of an interface increases as the scale of the problem decreases. Furthermore, the thermomechanical properties of the interface can differ significantly from those of the surrounding bulk. Such effects are described here using interface elasticity theory. The objective of this contribution is to detail the computational aspects of modelling thermomechanical solids with highly conductive energetic interfaces. The interface is termed energetic in the sense that it possesses its own energy, entropy, constitutive relations and dissipation. The equations governing the fully nonlinear, transient problem are given. They are then solved using an efficient finite element scheme. Full details of the consistent linearisation of the nonlinear governing equations are provided. Key features of highly conductive energetic interfaces are then elucidated via a series of three-dimensional numerical examples. In particular and in contrast to highly conductive thermal interfaces, it is clearly shown that a jump in the heat flux across the interface is possible even in the absence of a heat flux along the interface