Parametric study on the load-carrying capacity of plain-woven composites hybrid bonded-bolted joints

This work presents procedures and results from quasi-static uniaxial tensile experiments carried out on hybrid bolted bonded (HBB) joints using carbon fibre reinforced plastic (CFRP) adherends. The impact of various dimensional parameters, including lap length (L), lap width (W), number of bolts (N), bolt diameter (D), and bolt arrangement, on its ultimate load and failure modes of the HBB joint is investigated. The failure mechanism of the HBB joint is examined and summarized, offering theoretical insights for the engineering application of this structural configuration. The findings of the study indicate that the ultimate load capacity of the hybrid joint is notably enhanced by increasing both the lap length and lap width, and is further influenced by the effective dimensions at the edges and end distances. The transverse configuration of multiple bolts within the adhesive-bolt hybrid joint demonstrates superior maximum load capacity and average stiffness in comparison to a longitudinal arrangement. During tensile testing, the primary mode of failure observed in the Hybrid Bolted-Bonded (HBB) joint is adhesive failure, often accompanied by delamination. Cleavage failure is predominantly observed in configurations with longitudinally aligned multiple bolts arranged in a singular row. On the other hand, shear tear-out and bearing failures are commonly encountered in single-bolt joints characterized by a substantial width-to-diameter (W/D) ratio. Specifically, shear tear-out failure tends to manifest in cases with a small length-to-diameter (L/D) ratio, whereas bearing failure is more prevalent in instances with a large L/D ratio.