Dynamic behaviour of flax fibre-reinforced polymer pipes subjected to harmonic excitation

Abstract

Substitution of flax fibres for synthetic fibres in fibre-reinforced polymer (FRP) composites has recently been considered an effective step towards achieving more sustainable industrial practices, enabled by the fact that flax fibre has mechanical properties that are comparable to that for glass fibre. Three flax FRP (FFRP) pipes with the same length and internal diameter but having variations in the wall thickness were manufactured. The pipes had a fixed end and had a free end and were tested for 54 harmonic excitations with various dynamic properties when the pipes were buried or were unburied. The effect of shaking frequency, peak ground acceleration, wall thickness and soil cover on the dynamic response of the FFRP pipes was investigated. Finite element modelling was also used to verify the experimental results and to study the pipe behaviour when subjected to harmonic excitations. Results showed that while for the unburied pipes, the maximum pipe strain occurred at the cross-section next to the fixed end; for buried pipes, the largest strain developed at various cross-sections along the pipe length.