Synergistic enhancement of vibration characteristics in chemically treated PALF reinforced CNSL–epoxy hybrid biocomposites via Taguchi–Grey relational optimization

This study investigates the dynamic behaviour of Pineapple leaf fibre (PALF) – reinforced CNSL – epoxy hybrid composites developed using a hand lay-up method. The influence of fibre content (5-15 wt. %), chemical treatment (NaOH, KOH, KMnO 4 ) and curing temperature (40-80 °C) on natural frequency and damping characteristics is analysed using Taguchi L9 design coupled with Grey Relational Analysis (GRA). The first mode of natural frequency of the composites is found to vary in the range of 7 – 16 Hz, depending on processing conditions. Damping ratio (ζ), evaluated using the half – power bandwidth method, ranged from 0.018 to 0.028, indicates improved energy dissipation capability. Statistical analysis reveals that fibre content contributes predominantly to performance variation, followed by chemical treatment and curing temperature. The optimal parameter combination (A3B2C2: 10 wt. % fibre, KMnO 4 treatment, 60 °C curing) exhibits an improved fibre–matrix interaction and optimised microstructural characteristics. The results demonstrate that the developed hybrid composites possess favourable dynamic properties for vibration attenuation applications.