KL-2-1 The role of defect assessment in elevated temperature component design and remaining life estimation codes(Keynote Lectures 2)
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概要
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The development of high temperature defect assessment codes is a further step on the advances made in earlier codes of ASME, RCC-MR and BS-5500 [1-3] in which design and lifetimes of components operating at elevated temperatures are based on the analysis of un-cracked structures. Actual detection of small cracks and assumed minimum crack sizes in structures makes it imperative that fracture mechanics be taken into account in high temperature codes. This discussion is primarily aimed at remaining life assessment. Thus it may not be strictly applicable to producing the initial design criteria except in the sense of analysing the behaviour of postulated defects. But it can still be used at the design stage assuming the existence of hypothetical defects in structures once the minimum size of such defects are established. An overview of guidelines for assessing the structural design, relevant failure criteria and the significance of defects in high temperature components operating in the creep range are presented. The codes contain methodology for dealing with failure by net section rupture, incremental crack initiation and growth, due to creep and/or fatigue or some combination of both processes. The influence of fatigue and the onset of brittle or ductile fracture in determining tolerable defect size are also considered. Finally it is concluded that improvement and the future development of these codes will depend on improved verification using experimental and numerical techniques. Also in order to increase confidence in the deterministic calculations sensitivity analyses and probabilistic methods should always be included.
- 一般社団法人日本機械学会の論文
- 2001-06-03
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関連論文
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- KL-2-1 The role of defect assessment in elevated temperature component design and remaining life estimation codes(Keynote Lectures 2)