Multiscale modelling of electrically conducting generalised interfaces

• Applicant: Privatdozent Dr.-Ing. Tobias Kaiser
• Subject Area: Mechanics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556523284

Material interfaces occur at various length scales and may exhibit significantly different properties than the surrounding bulk. As typical examples, consider grain boundaries and wire bonds. Clearly, the unique properties of grain boundaries significantly influence the effective macroscale material response. Likewise, wire bonds are an integral part of electronic packages used in automotive, communication and computing applications, and are of cardinal importance for their functionality. Motivated by these examples, this research project focuses on the development of sophisticated computational approaches to predict developing properties of material interfaces and of materials featuring those in a multiphysics multiscale setting. Three fundamental, closely-related research questions are addressed: i) The theory of general imperfect interfaces was recently proposed as a unifying framework combining cohesive-zone- and interface-elasticity-type formulations. Focusing on electrical conductors, this approach is extended to electro-mechanical coupling in a first step. This allows for effects such as the electrical resistance of the interface, tangential electric currents to the interface and mechanically-induced failure processes that alter the electrical interface properties to be accounted for. ii) The effective macroscale properties of the material interface in the introductory wire bond example are governed by processes at a lower scale. Computational multiscale methods make it possible to account for the material microstructure and to resolve lower scale processes in simulations. Substituting purely phenomenological interface material models, a computational multiscale approach for the prediction of electro-mechanically coupled processes in material interfaces is developed in a second project step. iii) The presence of material interfaces, such as grain- and phase boundaries, affects the effective electro-mechanical properties of material systems. Their influence can, in principle, be studied by considering (generalised) representative volume elements featuring material interfaces. To this end, established computational multiscale formulations are extended in a third project step so as to account for the presence of electro-mechanical general imperfect interfaces.

• DFG Programme: Research Grants