Identification of mechanical properties of a braided alfa stem (Stipa tenacissima L.) by an inverse method

The aging of buildings and structures, accompanied by an increase in the prices of conventional building materials, has pushed the scientific community to explore new techniques and materials to rehabilitate existing buildings. Rehabilitation aims to extend the service life of a structure while maintaining its strength and stability. Among these techniques, composite materials based on synthetic fibers, such as carbon fibers, have been developed. However, materials with low carbon footprints that are bio-sourced and eco-friendly are of interest to the scientific community. The use of Alfa plant natural stems in a braided form is the focus of this study. This study is the first to use geometric shapes to improve the performance of a natural fiber-reinforced composite. Epoxy was used as the matrix, which is the material used most often in composite designed for reinforced concrete structures. This study aims to determine the equivalent mechanical properties of the Alfa braided stem using the reverse method. Test specimens of the epoxy/Alfa composites were manufactured and tested on a tensile machine. The epoxy was tested, and its properties were determined. Subsequently, a finite element numerical model of the specimen was constructed, and the properties of the braided Alfa stem were varied until identical results were obtained. The mechanical properties of the Alfa braided stem were thus identified. The results showed that the braided Alfa stem had a stiffness modulus of 23.243 GPa.