Experimental study on the influence of optimised automated fibre placement processing parameters on the impact response and residual flexural strength of AS4/APC-2 laminates

This study explores automated fibre placement (AFP) for manufacturing impact-resistant carbon fibre/PEEK (AS4/APC-2) laminates by modifying the in-situ consolidation parameters. However, manufacturing these laminates without compromising their mechanical properties is challenging owing to the synergistic effect of parameters. The results indicate that a fast deposition rate and high consolidation force are associated with improved impact resistance and a higher threshold energy for damage. Improvements in flexural strength (27.4 %) and modulus (22.6 %), are achieved in non-impacted specimens. Acoustic emission monitoring was conducted during flexural-after-impact test to correlate the internal damage with the mechanical performance of AS4/APC-2 composites. The experimental results indicated that a fast deposition rate combined with high consolidation force can withstand higher impact loads. The FAI test showed the highest residual flexural strength and stiffness under these parameters, as it effectively resisted low-velocity impact (LVI) damage. However, the slight trade-off observed in post-impact strength suggested the presence of resin-rich areas, which may affect the damage tolerance of the laminates. • Optimised AFP parameters are critically assessed based on the low-velocity impact response. Depending on the manufacturing parameters, the specimens exhibit a unique damage mode. • Slower deposition rate combined with low consolidation force, results in greater damage, including higher absorbed energy and permanent damage to the specimen. • Fast deposition rate and high consolidation force can withstand higher impact loads but may compromise post-impact strength. • The damage tolerance was investigated using the Flexural-after-impact method, along with the acoustic emission technique.