Improved accelerated life testing for cathodic delamination
The overall objective of this work is to establish the feasibility of modeling the cathodic delamination problem in polymer coated submarine components with a view to developing a more accurate testing standard for Accelerated Life Testing (ALT) and to determining the effectiveness of new approaches for combating cathodic delamination in a quantitative manner ... An approach has ... been taken to characterize cathodically delaminating rubber/metal interfaces and forms the basis for the current attempt to model cathodic delamination between polyurethane and titanium. Once this model is established it will allow for an accelerated life protocol to be developed where stress and temperature will be used to accelerate crack growth in laboratory specimens while retaining the same crack growth mechanisms that are seen in service. The elements of the approach are threefold: 1. Determining the mechanical behavior of the polyurethane and titanium. The former is more challenging due to its nonlinearly elastic behavior. 2. Conducting a stress analysis of the specimen to be used in the cathodic delamination experiment in order to design it to provide the anticipated range of energy release rate values. 3. Conducting the cathodic delamination experiments and determining the crack velocity profiles for the polyurethane/titanium interface as a function of energy release rate and temperature.