Our competence with corrosion starts where most corrosion engineers stop – somehow the corrosion protection failed, we have an existing bearing structure with widespread general corrosion, now what? In today’s world we strive towards not overusing our one planet, instead of use and throw away we aim to extend life of existing assets, as long as it is safe. What is really the consequence of corrosion, must if always be replaced by new steel, or can it operate safely some more years?
Our structural engineers cover novel approaches to Corrosion Management, Corroded remaining Strength of bearing structures with widespread general corrosion as well as Corrosion Data concerning gathering and use of ultrasonic thickness measurements.
Corrosion Management
We can help identify when the hazard rate increases at the end of the bath-tub curve for corrosion, indicating a change in corrosion management approach from avoiding corrosion to include handling the consequences of corrosion. We aid in planning scope for corrosion measurements, structural analysis accounting of observations and proposing remedial actions. Corrosion inspections may be risk-based utilizing clustering of similar historical data and ranking their probability of exceeding allowable thickness combined with structural category as consequence. Triggers for inspection scope, updating inspection plans, and for remedial actions are developed. Uncertainty can be addressed and aiding decision basis.
Corroded strength
Based on studies of corroded tensile tests observed material performance of corroded steel deteriorate. The uneven surface also introduced stress concentrations acting as initiators for fatigue cracks. Our in-house power spectrum is a unique way of describing the unevenness of the corroded surface. We have insight on the global redistribution of stresses due to widespread general corrosion, which is the basis of assuming linear scaling of local stresses with thickness reduction. Reduction in buckling capacity due to a combination of plate stiffener and flange corrosion can be described by Resistance Surface Method (RCM). A digital structural twin in terms of updated as-is or predicted thicknesses of individual elements can be implemented in your finite element model (FEM).
Corrosion Data and prediction
With experience from developing Ultrasonic thickness measurement (UTM) databases of more than 150 000 records we aid in data management, analysis and visualizations. From traditional statistics to hierarchical clustering using Earth Mover’s distance (EMD). We have in-depth knowledge on literature databases on marine corrosion as well as our in-house prediction model describing the extent of corrosion over time by a dynamic moving probability distribution. This can also be used as a prior and updating by Bayesian statistics. Colorful charts, KPI’s and visualizations by mapping data on structures can also help decision processes.