Reliability-based, operational performance metrics for ship structures

Program management is concerned with reducing or mitigating the risks associated with meeting cost, schedule and performance goals. This dissertation introduces reliability-based performance metrics to mitigate the risk associated with the platform structural performance during design, specifically for Navy surface ships. Structural reliability theory is shown to be applicable for the measurement of the operational performance of platform structural systems in terms similar to those used for other platform systems, such as electrical and mechanical systems. Operational performance of non-structural platform systems is discussed in OPNAVINST 3000.12 (OPNAV 1987) and is transformed in this dissertation to apply to ship structural systems.; The ship structure operational performance measures introduced in this dissertation may be summarized as follows. The operational durability performance measure is the probability that the structure will not require repair over the platform lifetime. The operational dependability performance of the ship structure is defined as the probability that once the mission has started, the structure will successfully resist extreme seaway loads for the mission's duration. The operational capability performance of the ship structure is the ability of the structure to support operational needs such as resisting combat or accidental loads, or supporting dependent systems. The performance metrics included in this dissertation are collectively termed operational metrics and do not include other types of performance such as produceability, efficiency, repairability, or maintainability.; This dissertation introduces and demonstrates that ship structure operational performance can be quantitatively assessed using reliability-based performance metrics in design, and serves as a starting point for achieving a completely quantitative, operational performance-based structural management environment. Ship acquisition management can be significantly improved using these methodologies, as they would allow the platform stakeholders a selection of Figures of Merit, upon which decisions can be based. Current US Navy acquisition strategies do not incorporate quantitative structural performance measures and thereby do not adequately mitigate the programmatic risk of not meeting operational performance top-level requirements.