Multi-scale methodology for enhancing damage tolerance of composite materials in submarine environment subject to underwater explosion

Submarine platforms form some of the most complex systems ever designed by man but, in line with the defence policy, there is ever increasing pressure to reduce procurement and ownership costs while maintaining capability. Composite materials have long been recognised as playing a key role in meeting these requirements by reducing time and cost of corrosion protection and repairs, as well as corrosion fatigue, while maintaining the vital stability margins and buoyancy requirements for the increasingly complex combat systems used on next generation submarines. Composites have the further advantage of multi-functionality, offering both structural and integral stealth properties management. In addition, composites mitigate the increasing cost and supply problems of complex high density castings such as Nickel Aluminium Bronze (NAB) long used in submarine applications due to its shock and corrosion resistant properties. Reinforced in its aims by the Defence Technology Strategy, the proposed research will provide the opportunity to understand and quantify, via fundamental science, the intermediate and high strain rate shock response of naval submarines composites in a complex submerged environment, whilst simultaneously seeking more optimised composite structures via novel fibre architectures and hybrid systems. Moreover, the proposed study will contribute to the MOD's specific requirement to both develop and sustain indigenous expertise in the area of submarine design as a key national capability. Finally, through understanding and modelling of material/structural and dynamic loading related issues at a range of scales, vital knowledge for effective assurance, test and repair of composite materials will be gained and embedded in certification procedures and Defence Standards. The use of proposed validated predictive modelling methodology is also expected to yield substantial savings during the design of new materials and structures through ever increasing progression to virtual testing and design and accordingly will greatly reduce the need for excessive large scale testing which are both expensive and environmentally unacceptable. In addition, this research is expected to provide the means for significant weight and life-long cost saving designs without compromising capability.