Example 1 - Base steel hull no anodes

Figure 3 shows the BEM model of a ship hull and propeller in a 50m deep, sea layer. Note: the idealised shape of the propeller. For the UEP analysis the hull and propeller surfaces are assigned appropriate properties; in this case bronze and steel respectively.

Whereas in a pure UEP analysis the sea surface could be represented using a plane of symmetry, by contrast for combined UEP and CRM analysis the sea surface must be modelled using elements. For combined analysis a "far boundary" must be defined on which components of the magnetics vector potential will be set to zero.

The mid depth UEP is shown in Figure 4 and the corresponding CRM field is shown in Figure 5. The distribution of the corrosion related electric and magnetic field can be visualised by plotting a graph of its components on an axis near to and parallel with the centre line of the ship as in Figure 6.

See also: Boundary element modeling,Corrosion models, Knowledge based models, Mechanistic models, Pitting fatigue models, Risk based models

Predicting corrosion related electrical and magnetic fields using BEM, Robert Adey and John Baynham, BEASY