Meso-Scale Finite Element Fatigue Modelling of Textile Composite Materials (Mesoschaal modeleren van vermoeiing van textielcomposietmaterialen met de eindige elementenmethode)

Textile composite materials are winning their popularity in the automobile industry, wind energy industry, aerospace industry as well as in the sportware industry. These materials provide a better out-of-plane performance than multidirectional and UD laminates, for instance the post-impact mechanical properties, on the one hand. On the other hand, they can be easily produced using low-cost production techniques. However, the fatigue properties of the textile composites, depending on the complex structure of the preforms, are usually determined through experiments, which are expensive and time-consuming.The aim of this study is to develop an algorithm for modelling the meso-scale progressive fatigue damage and to predict the fatigue lifetime and fatigue modulus in textile-reinforced composites, and to eventually develop an understanding on fatigue behavior of textile composites. Therefore, a single-layered meso-FE model is established focusing on the tension-tension fatigue simulation of textile composites.The hierarchical damage evolution in textile composites are at the most preserved and described by a meso-FE model based on a proper mesh and well defined mechanical properties of the constituents. The impregnated yarns are taken as transverse-isotropic homogeneous material, for which the intra-yarn matrix cracking can be determined by using a polynomial fatigue failure criterion. The fibre rupture needs to be separately considered. The delamination of warp and weft yarns can be represented by the shear damage of the very thin matrix layer between them. Nevertheless, based on a single-layered FE model of a unit cell, the inter-layer delaminations were not accounted for the time being.Each element in the yarn volume is treated as a tiny piece of UD composite, for which the fatigue characteristics (S-N curves) of the UD composite obtained from fatigue tests will be used as input data. The material nonlinearity in the post-damage phase will be realized by using a certain stiffness degradation scheme. The local damage and hence the stress redistribution are accounted.Two types of twill weave carbon epoxy composite materials, comprising of the same fibre-resin system, are experimentally investigated. The numerical outcome is validated by using the experimental data. Moreover, the fatigue model can be utilized to explain the different mechanical behavior caused by different preform architectures.nrpages: 292status: publishe