Scale-bridging modeling of magnetic shape memory alloys – from the microscopic scale to the system level (SMartMicroSys)

• Applicants: Professor Björn Kiefer, Ph.D.; Professor Dr.-Ing. Jürgen Maas
• Subject Area: Computer-Aided Design of Materials and Simulation of Materials Behaviour from Atomic to Microscopic Scale ; Microsystems
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 568654678

Magnetic shape memory alloys (MSMA), typically Ni–Mn–Ga, are active materials, which exhibit a unique coupling between mechanical and magnetic properties. When exposed to a magnetic field, a change in crystal structure causes MSMA samples to undergo significant straining, making them suitable for various applications, including micro-positioning actuators, sensors and energy harvesting systems. This unique characteristic has motivated intensive research efforts to explore their full potential.A wide range of models for MSMA exists on different scales, each with its own individual strengths. However, limitations arise as soon as these models are transferred to problems on different scales. This necessitates the development of scale bridging methods that utilize the strengths of the respective levels without compromising efficiency and accuracy. The FE² approach has generally demonstrated effectiveness in linking the micro and macro levels in the context of magnetomechanical coupling phenomena, while lumped-parameter surrogate models can bridge the gap between the macro and system levels based on just a few operating points. Standardization across models has been hindered by the fact that they are usually parameterized with widely varying material data and geometries. Additionally, experimental data is often scarcely accessible or have to be laboriously determined. The aim of this research project is therefore to develop cross-scale modeling approaches for MSMA that link models from the micro level with the macro level, and up to the system level within a consistent data structure.Building on the findings of joint preliminary work, this project aims to develop MSMA models on all three scales and establish novel bridging methods to link and compare them. These bridging methods aim to reduce the need for extensive experimental parameterization on larger scales by leveraging virtual experiments. Simultaneously, they will incorporate and investigate the real-time behavior of lower scales, which are computationally expensive. To achieve this, comprehensive validation and parameterization data will be obtained experimentally for various load cases, encompassing both spatially averaged behavior and location-dependent strain fields. The results of the research project will provide fundamental insights into an integrated, scale-bridging modeling approach for MSMAs. The approach's validity will be demonstrated through experimental data, and the achievable model quality at each level will be quantified.

• DFG Programme: Research Grants