Determination of Damage Parameters for Microcrack Formation: Measurement and Application in Lifetime Prediction Models
Under creep conditions, e.g. in pressurised components operating at high temperatures, the microstructural degradation of materials manifests itself in the formation of cavities and microcracks on the grain boundaries. The knowledge of the evolution of this microstructural damage is essential for the reliable assessment of the residual service life. Lifetime prediction usually involves the structural analysis by numerical methods such as the finite element method. Constitutive models describing the macroscopic materials behaviour are then needed in which this type of degradation is taken into account by damage variables defined on a macroscopic scale.
KeywordsUltrasonic Velocity Rupture Surface Damage Parameter Damage Variable Creep Damage
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- U. von Estorff, F. Lakestani, and H. Stamm, Material Specific Creep Damage Detection by Time-of-Flight Measurements, in: Bulletin du Cercle d’Études des Métaux, 8eme Colloque International, 20 et 21 novembre 1991, p. 2.1Google Scholar
- H. Stamm, An Overview of the Ultrasonic Detection of Creep Damage, European Journal of NDT Vol.1 (1992) pp.169–178Google Scholar
- U. von Estorff and H. Stamm, Determination of Creep Damage in Steels, Proceedings of the Fifth International Conference on Creep of Materials, Lake Buena Vista, Florida, USA, 18–21 May 1992, pp. 287–296Google Scholar
- H. Stamm and U. von Estorff, Determination of Damage Parameters for Microcrack Formation Under Creep Conditions, Behaviour of Defects at High Temperatures, ESIS 15 (Edited by R.A. Ainsworth and R.P. Skelton) 1993, Mechanical Engineering Publications, London, pp. 123–151Google Scholar
- P. Hähner, A Generalized Criterion of Plastic Instabilities and Its Application to Creep Damage and Superplastic Flow, accepted for publication in Acta metall. mater.(1995)Google Scholar
- A.-M. Morrissey, Thesis, Trinity College Dublin, 1995Google Scholar
- J. Bressers, R.C. Hurst, co-ordinators, COST 501-II, Work Package 5, EUCO/MCS/03/94,1994Google Scholar
- M.S. Shammas, in: Proc. of the Conf. on Life Extension and Refurbishment of Steam Plants, Institution of Mechanical Engineers, London (1987)Google Scholar
- J. Schwertel and H. Stamm, submitted to J. of Microscopy (1995)Google Scholar
- J. Schwertel and H. Stamm, to be publishedGoogle Scholar