Characterizing meso-mechanical properties of ultra-thin plain woven fibre composites under large deformations

Abstract

Ultra-thin woven fibre composite structures offer high strength-to-weight ratios and flexibility, making them highly used for aerospace and other applications requiring lightweight, durable materials. However, understanding and predicting the mechani- cal behaviour of these composites under large deformations, particularly their flexural response and bending stiffness, remains a challenge. This study presents a compre- hensive investigation into the meso-mechanical properties of ultra-thin plain woven composites under conditions of extreme curvature. Using finite element modelling, this research focuses on accurately capturing the bending behaviour and assessing the impact of inter-tow slipping and material non-linearity, which are pivotal in under- standing the reduction in bending stiffness observed at high curvatures. A detailed numerical model based on a Representative Unit Cell approach was developed in Abaqus software, incorporating Periodic Boundary Conditions to reflect the composites meso-structural attributes. To simulate realistic conditions, both geo- metrical and material non-linearities were introduced. This approach enabled a robust analysis of cohesive interactions between fibre tows and the resin matrix, which are crucial forreplicating theobservedreductioninbendingstiffnessathighercurvatures. The FE model was calibrated and validated against experimental results from the lit- erature, showing strong agreement with empirical data and confirming the model’s predictive capabilities. Results indicate that interfacial interactions, coupled with material non-linearity, play significant roles in the mechanical response of these composites, particularly un- derlargebendingstrains. Thestudysuccessfullycapturesthesephenomena,providing a framework for further parametric studies and highlighting the necessity of meso- scale modelling for such complex materials. The findings offer valuable insights for optimizing the design of ultra-thin woven composites for use in deployable aerospace structuresandotherapplications,contributingtothedevelopmentofmoreefficientand reliable structural components.