Papers by Author: Bamber Blackman

Abstract: Fibre metal laminates (FMLs), combining metal alloy sheets with fibre-reinforced polymers (FRPs), offer high specific strength and good fatigue resistance for lightweight structural applications. However, conventional manufacturing routes for thermoplastic FMLs rely on separately forming and bonding or hot pressing, which involve multi-stage forming routes, long heating cycles, high energy consumption and limited industrial scalability. To address these limitations, a novel non-isothermal one-shot forming route integrating hot form quench (HFQ) with FRP stamp forming is proposed in this study. In this process, separately heated metal and FRP blanks are stamped together in cold tools, enabling simultaneous forming and adhesive-free bonding within a single operation. U-bending forming trials were conducted using AA6082 aluminium alloy sheets and carbon fibre-reinforced polyamide 6 (CF/PA6) laminates. The influence of FRP temperature state and aluminium surface condition on forming quality and interfacial bonding performance was systematically examined. Solid-state FRP forming limited excessive polymer flow, resulting in stable bonding but a higher intra-ply void content, whereas molten-state forming promoted polymer redistribution and reduced void content at the expense of bonding performance, leading to local debonding in highly deformed regions. In addition, chromic acid etching of the aluminium surface improved bonding and mitigated debonding after forming and post-form T6 artificial ageing. These results highlight the importance of balancing polymer flow behaviour and aluminium surface condition in non-isothermal one-shot forming, providing a practical and energy-efficient route for manufacturing thermoplastic FML components.

Abstract: From the impact experiment for the nonlinear plastic behavior with the dynamically loaded adhesively-bonded TDCB specimens, there is the range of load from 1 to 2 kN or pin displacement from 4 to 10 mm for the most part in case of the impact rates 1, 2.5, 5, 7.5 and 12.5m/s. There is also the range of energy from 5 to 10 J or energy release rate(fracture energy) from 3000 to 6000 J/m2 for the most part in case of all impact rates. The fracture energy on automotive adhesive joints can be estimated by using the fracture toughness, GIC, experimental results under high rates of loading in this study. The key fracture mechanics parameter, namely the fracture energy, GIC, was ascertained as a function of test rate and may be used to assess and model the joint performance.

Abstract: An amorphous styrene-acrylonitrile (SAN) copolymer has been modified by various concentrations of metal oxide (MeO) nano-particles up to 0.50 vol.%. Atomic force microscopy of the modified thermoplastics showed that the nano-particles were well dispersed in the matrix. The incorporation of the nano-particles had a marginal effect on the glass transition temperature and yield stress. However, the Young’s modulus increased with the volume fraction of the nano-particles. The fracture and fatigue properties also had a marked increase with the addition of the nano-particles. The fracture energy was increased from 316±10 J/m2 to 445±27 J/m2, and the maximum fracture energy threshold was increased from 17±1 J/m2 to 34±2 J/m2 at 23 °C. Scanning electron microscopy (SEM) studies showed that debonding of nano-partilces, subesequent plastic void growth and large scale fibril deformation initiated by mulitiple crazing were observed in the process zone of the nano-modified composites.