Numerical and experimental evaluation of adhesively bonded, large scale, full composite joints in maritime applications

Composite materials have a wide range of uses in engineering applications. Their ever-growing implementation stems from their advantages including high strength, durability, and lightweight. However, especially in highly loaded maritime composite structures challenges still exist. [1]. One of the aims of the RAMSSES European project is to tackle the challenges of designing and building an 85 m-long full composite vessel that complies with Safety of Life at Sea (SOLAS) and Class regulations [2]. With this goal in mind, a section of a custom ship, including three novel joint designs, is conceptualized. These connections are full composite joints, and they connect the heavily loaded deck to the bulkheads and to the ship hull. Novelty comes from the fact that no metal is used in these connections since panels are adhesively bonded, bringing the weight even lower compared to current examples of such joints which include metal fasteners [3]. Such joints have other disadvantages such as complex assembly and corrosion issues which require additional measures such as coatings or other forms of conservation to ensure functionality. The performance evaluation of these joints is the topic of this paper. Three different joint types were proposed that, according to the analytical and finite element calculations, surpassed the performance required by the initial ship design. Subsequently, they were built to scale and tested in a bending configuration that introduces a loading condition, similar to that of the real structure. Non-crimp glass fiber fabrics in combination with toughened vinylester resin were used in Vacuum Assisted Resin Transfer Molding (VARTM) process to produce the joint components and methyl-methacrylate (MMA) adhesive was used for the bonding process. For each joint type three specimens were produced and tested. A failure prediction model was built in Abaqus for each joint type and the performance was validated against the experimental results. (C) 2023 International Committee on Composite Materials. All rights reserved.