Experimental characterization and modeling of GF/PP commingled yarns tensile behavior

Abstract

Three-dimensional (3D) fabrics of commingled yarns offer the possibility of a low-cost and fast manufacturing of complex-shaped composite parts. Textile-reinforcement behavior during the forming process is very important since the appearance of defects (for example wrinkles, yarn misalignment or breakage) can significantly affect the mechanical properties of the final part. Experimental characterization of the mechanical behavior of textile-reinforcements is expensive, time consuming, and a large scattering of results is often observed. To overcome this, meso-scale modeling is an interesting method to study and understand the textile behavior at the unit cell level. To perform realistic simulations, an accurate modeling and, therefore, knowledge of the yarn mechanical behavior are needed. In this paper, a simple protocol is proposed and validated in order to investigate the tensile behavior of commingled polypropylene/glass yarns. Influence of specimen length and strain rate are highlighted. A comparison of tensile behavior of yarns before and after weaving is carried out in order to evaluate the weaving damage effect. Finally, a model describing the commingled yarn behavior is proposed. The parameters of the model are defined. Their dependency to strain rate, specimen length, and weaving damage are highlighted.