State of the Art
The demo case is dedicated to smaller, fast ships with highly specialised, high-value and sensitive outfitting, operating under extreme conditions ‘all year round at 24/7’ (e.g., offshore patrol, coast guard, or environmental surveillance vessels). For strength reasons, hulls of these ships as well as superstructures are usually made of steel or aluminium. Superstructures are basically exposed to extreme conditions, such as wash and green water, wind, vibration, or temperatures. Composites would offer benefits such as lower weight, improved noise and vibration damping, or stealth effects. However, a lack of operational experience, condition monitoring and methods for a multi-criteria design optimisation currently act as barriers to wider use.
Objective
Conception, production, testing and validation of a demonstrator for composite superstructure meeting multi-criteria made up of a module on metallic deck.
Solution
The solution is a compact superstructure module consisting of fibre-reinforced plastic (FRP) foam sandwich panels, with integrated joints to the metallic deck, outfitting elements, and condition monitoring, including the necessary production, joining and repair techniques at competitive cost as well as an optimised design and approval approach for a variety of similar cases. Functional requirements include strength, fatigue, noise, vibrations, resistance to aging and survivability in case of fire.
In the project a composite demonstrator case regarding design requirements for the offshore patrol vessel was designed and calculated. In order to increase the weight saving, an optimisation of the numerical simulation was performed. Due to the large dimensions of the module (10.5m x 5.2m x 3.6m), only mock-ups are extracted from this architecture. The extraction of a representative part of the superstructure block has been made in order to regroup the main design details of the superstructure. Following a screening phase including bench tests, fire test and cone calorimeter tests, larger specimens have been produced and single burning item tests have been realized. According to this test campaign the unpainted panel presents good results where almost all the criteria comply with the standard requirement.
Potential
Limits for current FRP applications across the sectors will be pushed; also, wider application in fast special ships for a variety of purposes, including in the offshore industry will be enabled.