Helical buckling in textile cord-elastomer composites under compressive loadings: Experiments and simulations

In this paper, the study of helical buckling is extended, for the first time, to slender structures with a complex architecture: textile cords. This phenomenon is investigated experimentally through in-situ X-ray tomography compression tests and numerically through filament-scale finite element simulations, which are then compared with the experimental results. Additionally, a parametric study is performed on the matrix stiffness, exploring configurations beyond the experiment's domain. The results highlight that the buckling amplitude is inversely related to the stiffness of the matrix and the twist of the cord. These findings are discussed in relation to the theory for buckling in single filaments. The consequences of the buckled configuration on strain distribution at the filament scale are analyzed, highlighting how helical buckling influences load redistribution within the cord. In this sense, this work could open the field towards a conscious design of textile cords around the buckling point.