Textile and Composite Modelling on a near Micro-scale: Possibilities and Benefits

Textile materials are increasingly used in civil engineering for the purpose of reinforcing high performance composites, acting as membranes or fulfil technical tasks like filter contaminated media. Therefore, the demand for accurate numerical models which are able to predict the textile mechanics and the forming behaviour of dry and consolidated textiles is increasing and the requirements on the models accuracy and fineness rises. Many numerical models have been introduced in the literature for the different levels of objectivity. For macro-scaled models, complex material models have been carried out to account for the various deformation mechanisms and the anisotropic mechanic of textile fabrics. For meso- or micro-scaled models, the quality of the geometrical model is mainly influencing the simulation results. The quality of a numerical simulation in general strongly depends on the models accuracy. Therefore, providing an accurate model is the key factor for a successful simulation. For textile micro-scale modelling, the digital-element approach was introduced to account for the typical behaviour of technical multifilament yarns [1]. In this paper, methods for the unit-cell generation of textile models as well as composite models are presented for a near micro-scale resolution. The application of the digital-element approach with LS-DYNA® is explained. Possibilities and benefits of structural analysis on the micro-scale as well as challenges in using digital-elements are shown and discussed. Convergence examinations on the models fineness are carried out and the results of optical validations are shown. The method of Lagrange-coupling, which is implemented in LS-DYNA, is used to model a textile reinforced composite. The use of the keyword: *CONSTRAINED_LAGRANGE_IN_SOLID, is discussed and results of the micro-scale composite analysis with LS-DYNA are given.