An evaluation of the influence of manufacturing methods on interlocked aluminium-thermoplastic composite joint performance

Joining techniques for multi-material structures are critical for increased use of lightweight materials such as aluminium alloys and thermoplastic composites in the automotive industry. Interlocking adhesive joints (IAJs) can provide increased mechanical performance over standard adhesive joints, but manufacturing methods suitable for industrial applications must be developed. Here, three methods are examined for fabricating composite adherends with recessed macroscale features. The methods differ in the way the fabric material is draped over a mould and are referred to as “simple-stacking”, “moulding-in”, and “fibre-cutting”. The IAJs are tested under quasi-static, 0.5 m/s and 3 m/s loading rates and the fibre-cutting method achieves the best mechanical performance. One reason is that it gives a homogenous fibre distribution across the overlap width, providing good flexural properties at the recessed features. It also results in resin-rich regions along the overlap length, which lead to beneficial “snubbing” for improved interlocking, and progressive, energy-absorbing failure. The fibre-cutting method is simple to automate and well-suited for scale-up to industrial manufacturing.