Effects of environmental exposures on the barely visible impact damage of flax fibre reinforced biocomposite and its glass fibre hybrids

Abstract

Exposure of biocomposites to various environmental conditions is a concern when used for structural and semi-structural outdoor applications. This study investigates the effect of different environmental exposures on the low-velocity impact damage behaviour of flax fibre reinforced epoxy composite and its glass/flax hybrids. Flax and flax/glass hybridised epoxy laminates were fabricated using the vacuum infusion technique. A drop-weight low-velocity impact tests were performed on composite laminates at 5 J of incident energy with sub-zero temperatures, i.e., at (-10°C and − 20°C) and room temperature (R.T.). In order to evaluate the induced damage at different temperatures, micro-computed tomography (µ-CT) and visual inspection techniques were employed. The experimental results show that at a sub-zero temperature of -20°C, the flax and hybrid glass/flax composites showed more brittle damage behaviour than at room temperature. Furthermore, these experimental results have shown that alternating hybrid glass/flax laminates exhibited noticeable transverse cracks at R.T. and − 10°C., with higher absorbed energy and maximum impact load-carrying ability arising from positive hybrid effects. Also, it is evidenced from the results that the hybrid approach can be a viable strategy for achieving improved impact performance of natural plant fibre reinforced composites (NPFRCs) when exposed to different environmental conditions.