Rigid particles have been incorporated into laminated composites, especially to enhance their bending performance attributed to the stiffening of the matrix phase (i) and the increased interlaminar shear resistance (ii). In order to better evaluate the improvement mechanism provided by the particulate inclusions, this work investigates the incorporation of micro-sized silica on the top, bottom and both surfaces of glass fibre laminates, mitigating the interference of the interlocking effect. Three-point bending, and impact tests are performed to evaluate the hybrid glass fibre composites containing 5, 7.5 and 10 wt% of micro silica. In addition, the effect of the micro silica particles into epoxy polymers is verified under tensile, compressive and abrasion tests. A finite element model is developed to simulate the three-point bending test and to better assess the behaviour of the composite laminate. Although silica particles lead to increased compressive modulus of the epoxy polymers, their positive effect on glass fibre composites under flexural loads is more evident when placed on the bottom side of the laminates subjected to the maximum tensile stress. The incorporation of 7.5 wt% silica microparticles at the bottom surface of the laminates achieves higher flexural strength and lower impact resistance.

Full factorial designs are conducted to identify the effects of the incorporation of microparticles of silica, Portland cement and carbon laminate wastes (carbon microfibres - CMF), at 3, 6 and 9 wt% levels, on the mechanical performance of epoxy polymers and single carbon fibre joints at two grammage levels (200 and 600 g/m2). Particulate reinforced polymers (PRP) are characterised in tensile, compression, three-point bending and impact tests to better assess the influence of particles in the interlaminar region of hybrid composites composed of fibres and particles. The single joint test is performed to verify the presence of shear locking effect using particles between laminae. Compressive strength and modulus of PRPs increase when 3 wt% CMFs are added, revealing the most efficient level. The apparent shear strength is higher in composite joints made with 600 g/m2 grammage and CMF particles, promising reinforcement mechanisms for hybrid composites.

Composites have been widely used in engineering applications due to high strength to weight ratios. A large amount of materials used in aeronautics is based on composite materials. This provides motivation to improve the mechanical properties of the existing composite materials. When a glass fibre laminate is subjected to bending stresses, maximum compressive and tensile stresses are generated at its sides of the surface beam. Rigid particles have been added into laminate composites specially to enhance their bending performance attributed to the matrix stiffness and interlaminar shear resistance increases. In order to better assess the enhancement mechanism provided by particle inclusions, this work investigates the incorporation of micro-sized silica on the top, bottom and both surfaces of glass fibre laminates, mitigating the interference of the interlocking effect. Three-point bending and impact test were performed to evaluate hybrid glass fibre composites containing 5, 7.5 and 10% by weight silica. Although the silica particles lead to increased compressive modulus of epoxy polymers, their positive effect on glass fibre composite under flexural loads was more evident on the bottom beam side subjected to maximum tensile stress. The incorporation of 7.5wt% silica microparticles on the bottom surface of the laminates achieved higher flexural behaviour and lower impact resistance.