Multiscale hybrid modeling of magneto-active elastomers for enhanced understanding of tunable performance

• Applicant: Dr. Dirk Romeis
• Subject Area: Experimental and Theoretical Physics of Polymers
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 554602971

Magneto-active elastomers are composites of a soft polymer matrix with immersed magnetizable particles. The application of an external magnetic field significantly changes the properties of the material. Since magnetic fields are not screened by the matrix and can easily pervade the entire sample, not only the surface but also the bulk behavior is altered. This fact makes magneto-active elastomers a unique and highly functional aspirant for remotely tunable materials in versatile commercial applications. The concurrent presence of long-ranged interactions, considerable macroscopic deformations and field-induced microscopic repositioning of the particles in external magnetic fields represents a challenge for achieving a comprehensive description of magneto-active elastomers. It is the aim of the present project to develop a multiscale hybrid material model which allows for the first time to consider simultaneously large scale deformation processes and local particle repositioning in applied magnetic field for such composite samples. Going beyond previous approaches, we consider the association of affine deformation-induced rearrangements on macroscale combined with non-affine field-induced particle redistribution on microscale to attain the specific interplay between both mechanisms. Our approach will explicitly account for the self-consistent local and global magnetization effects, and subsequent interactions, due to the macroscopic sample shape and the microscopic particle distribution under deformation and repositioning. The proposed hybrid model is designed as a microscopic simulation method of hard particles immersed in a soft elastic medium with mutual hydrodynamic interactions. The particles are additionally connected to variable anchor points which are coupled to the deformation state to process and interchange the information from an effective energy minimization on the macroscale. The availability of a comprehensive material model with direct access to the microstructural particle redistribution and its effects on the global behavior of the sample facilitates an enhanced analysis of the practical prospects for magneto-active elastomers and will fundamentally help to improve the macro- and microscopic design of devices based on such composites.

• DFG Programme: Research Grants