The utilisation of numerical process simulation has greatly facilitated the challenging task of liquid composite moulding (LCM) process optimisation, providing ease of solution evaluation at a significantly reduced cost compared to complete reliance on physical prototyping. However, due to the process complexity, such process simulation is still considerably expensive at present. In this paper, cost-saving approaches to minimising the computational cost of simulation-based optimisation for LCM processes are compiled and discussed. Their specific applicability, efficacy, and suitability for various optimisation/moulding scenarios are extensively explored in detail. The comprehensive analysation and assimilation of their operation alongside applicability for the problem domain of interest are accomplished in this paper to further complement and contribute to future simulation-based optimisation capabilities for composite moulding processes. The importance of balancing the cost-accuracy trade-off is also repeatedly emphasised, allowing for substantial cost reductions while ensuring a desirable level of optimization reliability.

With the rapid advancement in the design and manufacturing of fibre-reinforced polymer composites, the limited research on the high-rate dynamic flexural behaviour restricts the effective use of these materials in high-performance load-bearing applications. Sustainable composites made from intralaminar-hybridised basalt-flax fibres, along with their hybrids incorporating carbon fibres, were fabricated using vacuum assisted resin infusion technique. A modified Split-Hopkinson Pressure Bar technique was employed for the high-rate three-point bending tests, while the quasi-static flexural behaviour was assessed with an electromechanical universal testing machine. In-situ damage characterisation for the dynamic testing was analysed with the aid of high-speed camera footages. The strain rate effect and energy absorption capability were also analysed. The novel basalt-flax/carbon fibre-reinforced epoxy composite achieved an ultimate flexural strength exceeding 2000 MPa at a loading velocity of 30.5 m/s, which represents a 21% improvement over its pure carbon fibre-reinforced counterpart and a 93% improvement surpassing its carbon/basalt fibre-reinforced counterpart. Their superior dynamic flexural properties demonstrate great applicability of basalt and flax fibres as sustainable reinforcing fibres in high-velocity impact applications, especially in the automotive and aerospace industries. Graphical Abstract