ASSESSMENT OF CRITICAL SIZE OF CORROSION PIT ON MECHANICAL ELEMENTS IN HYDRO POWER PLANTS
Energy efficiency is today one on key questions, not for engineers only buth rather to whole mankind. The failures of various parts of mechanical systems engaged in power insdustry are the lessons that should be learned thoroughly. Every behavior of structure beyond design envelope must be examined carefully in order to minimise losses in future and subsequently increase energy efficiency. Better design procedures or procedures that will gain more accurate results are major request to engineers and researchers last few decades. The latest veryfied method that have strong potentials in application on power industry components is so called Theory of Critical Distances (TCD). The TCD is not one method but a group of methods that have one thing in common - use of a characteristic material length parameter, the critical distance L for calculating the influence of notch like stress raisers under static and fatatigue loading. A case study from hydro power turbine shaft plant was chosen as subject for developed methodology presentation. This paper illustrates the application of TCD on the assessment of decrease of fatigue life of turbine shaft due to stress concentration on corrosion pits on shaft to flange radius.