Durability of Natural Fibre Epoxy Composite Structural Columns: High Cycle Compression Fatigue and Moisture Ingress
Composites Part C: Open Access
Many studies have investigated durability effects on the mechanical properties of natural fibre composite laminates using material tests, notably tension coupon tests. Few studies have investigated durability effects on the structural properties of natural fibre composite load-bearing structural members. In the case of thin-walled structural columns in compression, the degradation of mechanical properties may also influence structural properties such as compression buckling and post-buckling,
... nd post-buckling, which cannot be assessed via material testing. The present paper investigates the effects of high cycle compression fatigue and moisture ingress on the structural properties of natural fibre-epoxy composite structural columns of flax and jute, tested in pure compression. It is shown that up to one million cycles of compression load equivalent to one half of the ultimate compression load, has negligible influence on the (post-fatigue) compression strength. Conversely, moisture ingress notably effects the compression stiffness, buckling behaviour and strength. The compression stiffness of saturated columns reduced by up to 44%, the buckling load reduced by up to 48%, and the ultimate strength reduced by up to 45%. The large strength reduction is attributed to the combined effects of material degradation and increased susceptibility to compression buckling in moisture affected columns.