Structural Deterioration Modelling Issues for Reliability Based Management

This paper discusses various issues in developing a structural deterioration model for naval surface ships for use in a reliability based management method. Over time a naval ship structure will reduce in strength due to deterioration processes that will gradually increase the risk of failure. Increased maintenance is then required to ensure an acceptable level of structural integrity. Due to increasing economic pressures to reduce the cost of ownership, and to extend the life of a platform, there is a need to develop cost effective maintenance plans. Structural reliability techniques are currently being developed to achieve this. The various aspects and information needed to develop this approach are discussed. The dominant deterioration mode on an ageing structure is corrosion with paint coating breakdown. The operational profile of the ship is a dominant factor in the amount of deterioration that occurs. Naval operations will affect coating breakdown and corrosion. This information is discussed with regards to the probabilistic data required for the development of models of these processes. Typical survey data is also presented with a view to determine the critical areas for research focus. Finally, a way ahead is developed for the use of this modelling in developing maintenance planning of naval structures.