Simulation-Guided Process Optimisation for Thermoforming of Aligned Discontinuous Fibre Composites

Aligned discontinuous fibre-reinforced composites (ADFRCs) combines near-continuous fibre mechanical
properties with the formability and recyclability needed for sustainable manufacturing of composites.
Structural properties have been demonstrated at coupon scale, and recent studies have shown that ADFRCs
can be formed into complex geometries. However, these forming trials remain largely empirical. The interplay
between matrix viscoelasticity, fibre overlap evolution, and the requirement to form below the melting
temperature to preserve fibre alignment creates a narrow process window that is difficult to navigate through
trial-and-error alone. This study presents a forming simulation framework to accelerate process development.
ADFRCs comprising 3 mm carbon fibres in a bio-based poly(L-lactic acid) matrix were manufactured via the
HiPerDiF process. Viscoelastic constitutive models implemented within Abaqus/Explicit predict fibre sliding,
overlap evolution, and forming feasibility. Parametric optimisation identified that a forming temperature of
140 °C, a rate of 375 mm min⁻¹, and corner-constrained boundaries yield defect-free laminates. This was
confirmed experimentally in a single forming trial without iterative optimisation. The framework
demonstrates that simulation-guided process design can replace empirical trial-and-error, accelerating ADFRC
industrialisation.