DID YOU KNOW? DTIC has over 3.5 million final reports on DoD funded research, development, test, and evaluation activities available to our registered users. Click HERE
to register or log in.
Verification of the Boundary Element Modeling Technique for Cathodic Protection of Large Ship Structures.
NAVAL SURFACE WARFARE CENTER CARDEROCK DIV ANNAPOLIS MD
Pagination or Media Count:
Boundary Element computer modeling is gaining acceptance as a tool for predicting the distribution of cathodic protection potentials on a variety of large immersed structures. This technique should be valuable for placement of cathodic protection anodes and reference cells on ship hulls. Much has been published on this technique, including experimental verification on a laboratory scale. However, there has been little published information on experimental verification of the model predictions on large structures, especially for ships. A 42-foot 14-m barge was outfitted with a steel rudder, copper-based alloy propeller, zinc sacrificial anodes, and an array of reference cells to measure the distribution of potential over the surface of the hull and appendages. The barge was exposed in natural Seawater for four months. A computer model was developed to predict the distribution of protection, using a boundary element analysis program BEASY and long-term, potentiostatic polarization curves as boundary conditions. The model predictions are compared to the measured potential distributions. Polarization curves are presented which give good agreement between model predictions and the actual measurements on the uncoated steel barge hull under low flow conditions. More information on polarization behavior for surfaces under flowing conditions is needed for accurate predictions to be made over a full range of ship operating conditions.
APPROVED FOR PUBLIC RELEASE