Monte Carlo Micro-Stress Field Simulations in Flax/E-Glass Composite Laminae with Non-Circular Flax Fibres

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Mechanics

Background:

• Hybrid composites combining natural (flax) and synthetic (E-glass) fibres offer potential for advanced material design.
• Understanding the influence of natural fibre micro-scale irregularities on composite mechanical behaviour is crucial for performance prediction and optimisation.
• Existing models often simplify natural fibre geometry, potentially overlooking critical aspects of their mechanical response.

Purpose of the Study:

• To investigate the mechanical behaviour of intra-laminar hybrid flax/E-glass composites.
• To analyse the influence of flax fibre geometry and elastic properties on composite performance using computational micromechanics.
• To assess the impact of micro-scale irregularities in flax fibres on stress distribution and overall material behaviour.

Main Methods:

• Development of a Non-Circular Fibre Distribution (NCFD) algorithm to generate realistic microstructures.
• Utilisation of a 3D representative volume element (RVE) model implemented in Abaqus/Standard.
• Application of Monte Carlo simulations to analyse the effects of fibre variability on mechanical properties and stress concentrations.

Main Results:

• Monte Carlo simulations accurately predicted homogenised elastic constants, validating the approach against experimental data and Halpin-Tsai predictions.
• Fibre shape variabilities minimally affected overall homogenised properties but significantly increased localised stress concentrations at the fibre/matrix interface and within the matrix.
• Intra-laminar hybridisation exacerbated these localised stresses, particularly in flax/epoxy regions.

Conclusions:

• The natural shape of flax fibres plays a critical role in the mechanical performance of hybrid composites.
• Micro-scale irregularities in flax fibres lead to increased stress concentrations, potentially initiating damage mechanisms like matrix cracking.
• These findings provide valuable insights for designing and optimising flax/E-glass composites to enhance durability and load-bearing capacity.