MULTIPHYSICS COMPUTATIONAL HOMOGENIZATION METHODOLOGIES

Summary

Rough contact interface topographies are potential sources of large thermal energy dissipations within a variety of modern engineering applications ranging from micro-electromechanical systems and microprocessors to general microelectronics and electronic packaging.  Therefore, the development of methods for alleviating the sources of dissipation has accompanied the progress in these fields.  The predominant technology that has appeared over the years for this purpose is a class of materials commonly referred to as thermal interface materials (TIMs).  The fundamental functional contribution of TIMs is to provide a high degree of conformity among the contacting surfaces by filling the gaps that would otherwise be present due to roughness.

From classical solder-based materials and coatings to modern polymeric substances such as gels, adhesives and elastomers, a detailed understanding of the thermomechanical response of TIMs, and that of the raw contact interface in general, under a prescribed confinement pressure and heat flux requires a consideration of the microstructure of the contact interface and a modeling of the interaction between the surfaces at the microscopic level.  From an engineering point of view, the overall macroscopic reflection of the microscale physics at the interface is conveniently characterized within a continuum thermomechanics setting by a thermal contact conductance parameter. 

The present project aims at the estimation of the thermal contact conductance for a variety of finitely deforming rough interface topographies.  Additionally, the heterogeneous nature of TIMs require a coupling with homogenization schemes that reflect the effective thermomechanical response of these polymeric substances.  The proposed combined volumetric / contact computational homogenization framework is suitable for the analysis of similar energy transport phenomena across heterogeneous contact interfaces where the investigation of the sources for energy dissipation is of concern.

Figure: Phases of the micromechanical interface testing procedure are depicted, where a sample from a boundary layer is subjected to the macroscopic surfacial stretch followed by contact with a heat sink.

Publications

[1] I. Temizer, P. Wriggers (2009): Thermal Contact Conductance Characterization via Computational Contact Homogenization: A Finite Deformation Theory Framework. Int. J. Numer. Meth. Engrg. [accepted] ; abstract

[2] I. Temizer, P. Wriggers (2009): Homogenization in Finite Thermoelasticity. J. Mech. Pyhs. Solids [submitted]