Sources of Scatter in Creep/Fatigue Crack Growth Testing and Their Impact on Plant Assessment
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The procedures used in high temperature plant assessment are mostly deterministic thus requiring appropriate, specific data input to determine the remaining life of components containing design allowable defects. However, because high temperature test data contain uncertainties and scatter by their nature, the life assessment predictions may differ largely. In most cases it is based on the worst combination of input data resulting in a high conservative prediction. Thus achieved predictions do not take any optimisation of costs or improvement of plant efficiency into account. The present paper reports on the assessment procedures and the sources of scatter in creep/fatigue crack growth data. Their impact on the life assessment of the engineering structures following the deterministic and probabilistic methods is reported.
IIW-Thesaurus keywordsCrack initiation Crack propagation Creep Evaluation Fatigue cracks High temperature Lifetime Prediction Reference lists Statistical methods
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