Industrial applications, for example in the automotive or aircraft industry, usually require a precise prediction of the material behavior in order to make the materials’ use as resource-efficient as possible. Therefore, simulation methods are needed that enable multi-physical simulations on the one hand, while performing these simulations in an efficient amount of time on the other hand. We present a two-scale thermo-mechanically coupled simulation approach, which combines a finite element (FE) simulation at the macroscale with a Fast Fourier Transformation (FFT)-based simulation at the microscale [1,2]. Assuming scale separation, the boundary value problems at these two scales are first computed individually. Subsequently, averaging the macroscopic quantities over the corresponding local fields enables the scale transition. After presenting the general structure of the simulation approach, we would like to proof the ability of the two-scale method to model highly resolved thermo-mechanically coupled problems and its application in the field of microstructural evolutions in phase-transforming polycrystalline materials [3]. REFERENCES [1] J. Spahn, H. Andrä, M. Kabel, and R. Müller. A multiscale approach for modeling progressive damage of composite materials using fast Fourier transforms. Computer Methods in Applied Mechanics and Engineering, 268, 871–883, 2014. [2] J. Kochmann, S. Wulfinghoff, S. Reese, J. R. Mianroodi, and B. Svendsen. Two-scale FE–FFT- and phase-field-based computational modeling of bulk microstructural evolution and macroscopic material behavior. Computer Methods in Applied Mechanics and Engineering, 305, 89–110, 2016. [3] J. Waimann, C. Gierden, and S. Reese. Simulation of phase transformations in polycrystalline shape memory alloys using fast Fourier transforms. Proceeding of ECCOMAS Congress (Scipedia), 1-9, 2022.