Experimental investigation into quasi-static transverse loading of natural fibre reinforced composites with bio-inspired stacking configuration

Vegetal fibre composites are in significant demand by the industry due to their renewability and biodegradability. An important characteristic of fibre reinforced composites is that various mechanical responses can be obtained by altering the constitutive stacking sequence of laminates. The bio-inspiration of the composite designs represents an increasing trend due to their capacity to improve the overall strength of the structure. In this study, samples with bioinspired and non-inspired, quasi-isotropic, stacking configurations were manufactured. Hand layup of flax fibre epoxy pre-preg, consolidation using vacuum bagging and polymerisation in autoclave were used as the manufacturing method. The test samples have been tested under a constant quasi static regime of 2 mm/min with three mechanical response regions being identified. Two samples from each stacking configuration have been tested and the mean mechanical response has been considered in the investigation. The contact force-displacement data, energy absorbed, maximum contact force and related displacement are reported. The bio-inspired stacking sequence [±45/40/80]s laminates showed with 62% higher peak load than the conventional stacking laminate. The main energy dissipating mechanisms, observed by looking at the front and rear of the samples, were matrix cracking, delamination and fibre failure. It can be detected, in terms that the quasi-isotropic stacking sequence exhibited a limited damage area compared to the bio-inspired samples.