This repository contains the Bill of Materials (BOM) and the joint components of the physical structures part of the FiberEUse library, the materials library of the H2020 European project FiberEUse. The virtual part of the FiberEUse library is visible at: https://fibereuselibrary.com/ The concept of this materials library, including the physical structures, was designed and developed at +LAB, Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano (Italy). This repository supports the Ph.D. dissertation:Romani A (2024, foreseen). Circularity by Design, Materials, and Additive Manufacturing: Fostering sustainable and circular materialities enabled by additive manufacturing. Ph.D. dissertation in Design, Politecnico di Milano, Italy This repository also supports the following publications: Romani A, Rognoli V, Levi M. (2023). Materials Libraries: designing the experiential knowledge transfer through prototyping. In: Ferraris, S., Rognoli, V., Nimkulrat, N., editors. From Abstractness to Concreteness: experiential knowledge and the role of prototypes in design research. International EKSIG 2023 Conference Politecnico di Milano. Politecnico di Milano; p. 398-411. ISBN 978-88-9416-7436 Romani A, Rognoli V, Levi M. (2023). Speculative tinkering on circular design materials through 3D printing. In: Vaes K., Verlinden, J., editors. Cumulus conference - Connectivity and Creativity in times of conflict, Academia Press; 2023, p. 317-321. https://doi.org/10.26530/9789401496476-063 Romani A, Rognoli V, Levi M. (2023) Fostering circular materials within the design practice: materials and product library system. In: Lazet, A., editor. Design for Adaptation Cumulus Conference Proceedings Detroit 2022. Cumulus, p. 862-863. ISSN 2490-046X Romani A, Prestini F, Suriano R, Levi M. (2022) Material Library System for Circular Economy: Tangible-Intangible Interaction for Recycled Composite Materials. In: Colledani, M., Turri, S. (eds) Systemic Circular Economy Solutions for Fiber Reinforced Composites. Digital Innovations in Architecture, Engineering and Construction. Springer, Cham. https://doi.org/10.1007/978-3-031-22352-5_18 Note on STEP/STL files:CAD files of the physical structure (joints) were designed in Autodesk Fusion360. STEP/STL files are provided for all the joints to allow their importation into any CAD program.