Short fibre/unidirectional hybrid thermoplastic composites: Experimental characterisation and digital analysis

This paper explores the use of compression moulding to produce structural hybrid composites based on short-fibre composites, combining a short-fibre core and uni-directional (UD) skins. A parametric study on processing parameters found low consolidation pressures provided a higher repeatability of the manufacturing process. The best mechanical response of the hybrid laminate was obtained through a 2-step consolidation process due to an increased fibre volume fraction. Despite a moderate 21.5% increase in cost compared to the short fibre material, the hybrid panels showed large increases in mechanical properties with an outstanding increase in flexural modulus of 330.4%. A semi-analytical constitutive model of the short fibre composite was developed to determine the variability in the mechanical response due to the stochastic microstructure. The results predicted a low scatter in strength, compatible with the requirements of structural applications. This study opens the path to the development of sustainable thermoplastic composites from recycled short-fibre compounds. •A manufacturing study of hybrid composites with a short fibre core and UD exterior.•A 2-step moulding process increased fibre volume fraction and mechanical properties.•A constitutive model assesses digitally the variability of the stochastic material.