During a research stay of three months at the Universitat Politecnica de Catalunya (UPC) in Barcelona, Spain, our colleague Oliver Schwahofer had the chance to work with the research group of Composites and Advanced Materials for Multifunctional Structures. During the research exchange our colleague investigated numerical optimization methods for 3D-printable structures with special attention of elastically tailored micro-cells, using the topology optimization tool Swan (https://swanlab.github.io/Swan/), developed by Alex Ferrer. Beyond that, the elastoplastic behaviour of short-fibre reinforced composites was analysed with the highly-effecient spring element numerical homogenization tool, under the supervision of Fermin Otero. Some of these investigations were included in our contribution at the ECCOMAS Composite Conference (https://www.scipedia.com/public/Schwahofer_et_al_2023a).