This paper examines the flexural behaviour of uncured metal-carbon fibre reinforced polymer (CFRP) laminates when subjected to clamped-beam bending conditions. The test method was developed to assess how clamping affects the ratio between stretching and drawing during a proposed press forming process. The study compared the effects of variations in metal composition, layup, fibre orientation, and processing temperature on bending force, spring-back depth, and sliding length. The results revealed that increasing clamping pressure from 0 bar to 6 bar for aluminium-based hybrid materials with a 2/1 layup decreased the interlaminar sliding length by 3%, resulting in a rise in plastic strain in the metal layer from 2.55% to 15.22% and a reduction in spring-back by 10%. Additionally, the maximum bending forces for the uncured 2/1 metal-CFRP laminates were found to be slightly higher than twice that of the corresponding single-layer metal sheets. The processing temperature, ranging from room temperature to 110°C, was also shown to affect the bendability of the laminate, particularly at a clamping pressure of 0 bar. Furthermore, both numerical and experimental results demonstrated a strong correlation at room temperature across various clamping pressures for the hybrid materials studied.

This study focuses on the spring-back as a function of the degree of cure on single-curved metal-composite laminates. The manufacturing through a hot-pressing process involves different (curing) stages and can reduce the spring-back with the proper combination of forming and curing. The cure-dependent spring-back is measured and analysed as a function of material constituents, fibre directions, laminate layups, and the process parameters including temperature, holding time and pressure. The results demonstrate that the spring-back ratio after full-cured process is relatively small and mainly depends on the mechanical properties of the metal sheet in laminates. However, temperature and time have a significant effect on the spring-back of partially-cured laminates and the same type of fibre prepreg combined with two different metal sheets have similar trends of spring-back reduction. Moreover, the study found that the hybrid laminates with aluminium sheet delaminate at low pressure after full-cured, while the delamination disappears as the pressure increases. The characterisation on cure-dependency of the spring-back contributes to a better understanding of the deformability of the metal-composite laminates during the hot-pressing process and offers an opportunity to tune the spring-back of these laminates.

The bias-extension test is one of the test methods to characterise the intra-ply shear behaviour of continuous fibre reinforced composites including fabrics and unidirectional (UD) materials. For the determination of the major mechanical properties of metals, often a uniaxial tensile test is used. Combination of these two methods for the shear deformation of hybrid metal-composite laminates is proposed comparing the method for cross-plied unidirectional prepregs and woven fabric prepregs. The effects of material constituent, shear rate, preheat temperature and normal pressure on the intra-ply shear behaviour are investigated. The results indicate that the material constituents and the frictional responses depending on processing parameters play a critical role in the shear characterisation of the hybrid laminate. The shear angle measurement at four typical strains demonstrates that the support of metal layers improves the shear deformability by delaying the onset of fibre wrinkling. This modified intra-ply shear test contributes to a better understanding of the process design for wet (uncured) hybrid metal-composite laminate manufacturing.

Forming process with pre-stacked and uncured thermoset fibre metal laminate offers improved deformability compared to full-cured laminate especially for the production of complex structural components. This work investigated the friction behaviour at the metal-prepreg interface of glass fibre reinforced aluminium laminate through an inter-ply friction test. The influence of sliding velocity, normal force, fibre orientation and resin viscosity coupled with temperature on static and kinetic friction coefficients were studied. The kinetic friction behavior in the transition region between mixed and hydrodynamic lubrication, showed a good agreement with the Stribeck-curve theory. While for the static friction, a modified Coulomb friction model was found to fit the experimental results. These models were translated into a phenomenological inter-ply friction model which was incorporated into Abaqus/Explicit as a user-defined friction subroutine for verification. The findings contribute to the development of the forming process with fibre metal laminates.