Tensile Properties of a New Configuration Composite Bolted T-Joint Using Non-Standard Wide Washers

A new configuration composite bolted T-joint, comprising a laminated skeleton, load-carrying laminated beams, and a co-cured fabric skin, has demonstrated potential for primary load-carrying connections. However, research on enhancing its tensile performance remains insufficient due to its unique structural design. This study proposes an assembly scheme utilizing continuous non-standard wide washers to more fully exploit the tensile load-carrying capacity of this new configuration T-joint. Tensile tests were subsequently conducted, and a detailed finite element model was established and validated against experimental results. Experimental and numerical results reveal that, compared to circular washers, wide washers enhance the delamination resistance of both the skin and laminated skeleton in the base panel, which elevates the proportional limit load and limit load of the new configuration T-joint by 9% and 10%. Skin delamination induces the first marked slope reduction in the load–displacement curve, while delamination failure of the laminated skeleton leads to an overall load descending trend. When the beam thickness increases from 1 to 5 mm, the limit load can be increased by 46%. When the length and width of non-continuous wide washers are sufficient to distribute concentrated compressive forces, their effectiveness becomes nearly equivalent to that of continuous wide washers.