Experimental study and failure mode analysis of off-axis compression behaviour in natural fibre polymer composite

This paper aims to develop and study the off-axis compression behaviour in natural fibre polymer composites. A study was conducted to investigate the effect of various fibre orientations on the compressive properties of the natural fibre composite. The primary phase of the composite is epoxy resin, while the secondary phase (filler) is the oil palm empty fruit bunch (OPEFB) fibres. The OPEFB-fibre composites were prepared using the vacuum-assisted resin transfer moulding (VARTM) technique. Compression test according to ASTM D695, scanning electron microscope (SEM), and Fourier transform infrared (FTIR) analysis were conducted on the specimens. The compressive strength results indicate the anisotropic behaviour of the polymer composite due to different fibre orientations, with the highest compressive strength, 75.66 MPa, found in 15° specimens (OPEFB 15), with SEM images capturing the kink-band failure, which is induced by fibre microbuckling. In contrast, the lowest compressive strength, 35.92 MPa, was found in 90° specimens (OPEFB 90), showing matrix tearing/ cracking failure through SEM observation. The observed failure modes of the composites were analysed and found to be consistent with the compressive strength results through both the SEM and the optical microscope images.