Experimental and Numerical Investigation on the Mechanical Behaviour of Woven Fabric Carbon Epoxy Composites

Abstract

Laminated composite offers good in-plane properties but are prone to delamination due newlineto their poor mechanical properties in the thickness direction. In an attempt to overcome newlinethis drawback, woven-fabric (WF) composites, also termed textile composites, are put to newlineuse, as they offer a 3D reinforcement in a single layer and provide better mechanical newlineproperties in both in-plane and transverse directions. Therefore, it is essential to study newlinethe mechanical behaviour of such composites in order to fully realize their potential. newlineUnit cell modelling of the woven fabric composites is a promising tool for studying newlinefabric behavior at meso-level. However, due to the particular behavior of complicated newlinefibrous yarns and their multi-scale nature, numerical procedures applicable to woven newlinefabrics differ from conventional finite element (FE) routines. This thesis employs a newlinemulti scale modelling approach in predicting the mechanical properties of woven fabric newlinetextile composites and moreover concentrates on the micro and mesoscopic scales newlineleading to the results applicable to the macroscopic scale. Initially at the mesoscopic newlinescale a large portion of the work comprises of characterising the geometry of textile newlinefabrics. For this purpose an open source coded package, named TexGen developed at newlinethe University of Nottingham (U.K.) has been identified in the present work. The newlinegeometric models developed by TexGen are then used to predict in-plane elastic newlineproperties of textile unit cells using a FE analysis software ABAQUS®. Validations are newlineperformed for a series of dry woven fabrics as well as composites subjected to tensile, newlinecompression and in-plane shear loading. In the present thesis the yarns are treated as newlinesolid volume and their modelling depends upon many parameters such as yarn path, newlineyarn cross-section and yarn surface. However some issues such as interpenetration newlinebetween the yarns, roughness of the yarn path in fabric and change of spacing and newlinediameter of yarns during large deformation still need to be addressed. newline