Bond behaviour between flax-glass hybrid fibre reinforced epoxy composite and laminated veneer lumber joints

In this paper, single-lap shear tests were performed to investigate the bond behaviour between flax-glass hybrid fibre reinforced polymer composite (HFRP) and laminated veneer lumber (LVL) joints. Epoxy was used as polymer matrix of the HFRP and adhesive to bond LVL and HFRP to be joints. Digital image correlation (DIC) technique was used to measure the strain distribution of the LVL-HFRP joints for determining their bond-slip relationship. The effects of fibre fabric sequence of the HFRP and bond length on average shear strength, maximum shear stress, bond-slip relationship and fracture energy of the LVL-HFRP joints were evaluated. The test results showed that the bond length had a significant influence on the average shear strength, i.e., as the bond length increased, the average shear strength of the joints decreased. The fibre fabric stacking sequence of HFRP also affected the bond behaviour of the joints significantly at a bond length of 200 mm. It was found that the specimens of LVL bonded with flax fabric layer of HFRP had higher average shear strength, maximum shear stress and interfacial fracture energy than the LVL joints bonded with the glass fabric layer of HFRP.