Monitoring of component material degradation

The operational history of power unit equipment components is recorded in the material structure, resulting in a successive loss of material mechanical properties. The mechanism of exhausting the service life of the material has been identified, and the mathematical description of this process enables the current condition to be evaluated with a specific accuracy on the basis of its operational history.

 

The destructive effects of operation are measured by two parameters:

 

• The sum of material damage resulting from the stress and high temperature impact – or the creep degradation
• The sum of damage resulting from cyclical stress changes at a high temperature – or the fatigue degradation

 

 

Both kinds of destruction act together, and their numeric value is the measure of material degradation (Usage Factor).

 

Screen graphics of the material degradation module

 

 

In the module for boiler start-up monitoring, mechanical and thermal stresses in the selected components - recognized as criterion components - are continuously identified. These parameters are the basis of calculation of the combined stresses. These total stresses cause the degradation of material, and the effect of degradation may be estimated based on examining the history of stress changes during operation.

 

The program module calculates the following parameters:

 

• The total stress in the criterion pressure components
• Estimated material degradation as a result of high-temperature creep
• Estimated material degradation as a result of low-cycle fatigue
• Total degradation of the monitored components (Usage Factor)

 

 

The calculations - which are conducted continuously - enable hazardous areas to be evaluated on an ongoing basis and the method of unit operation to be corrected in order to limit these hazards in the future.

 

The picture shows an example of screen graphics where the values of relative material degradation due to fatigue and creep are presented. The bar chart shows the aggregated material degradation for each component in its relative form.

 

 

download brochure "Monitoring of Component Material Drgradation" (0,2 MB)