2 Prognostic Control of Cracking in Structures and Components Operating in Hydrogen Environments

Requirements for structural health monitoring and prognostic life assessment for hydrogen containing pressure vessels are described. One major issue is the complexity of models required to accurately describe crack growth in hydrogen and the type of prognostic model that will provide most accurate prediction of remaining useful life in these environments. The accuracy of a physics based prediction technique in comparison with a hybrid physics/ data driven technique has been investigated via a series of Monte Carlo simulations using a simple Paris law fracture mechanics model as the physics based approach. It is found that in hydrogen environments the hybrid/ data driven approach is most accurate, whereas the physics based approach is the best in air. Reasons for this difference are briefly discussed.