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P. Chellapandi¹, S.C. Chetal¹, Baldev Raj¹
Structural Longevity, Vol.3, No.1, pp. 1-36, 2010, DOI:10.3970/sl.2010.003.001
Abstract Some of the safety critical components of sodium-cooled fast reactors (SFR) are large dimensioned thin-walled shell structures. These components hold a large sodium mass and are subjected to high temperatures (820 K), high temperature gradients and cyclic thermal loads. The components are designed for long design life (>40 y). These features introduce complicated cyclic thermo-plastic deformations, the need for applying the principles of fracture mechanics under high cycle thermal fatigue, structural instabilities, fluid-structure interactions including elastic instabilities and high strain rate deformations. Hence, the structural design of such components is performed by addressing the relevant concepts in mechanics. In this… More >

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S. K. Patel¹, B. Dattaguru², K. Ramachandra¹
Structural Longevity, Vol.3, No.1, pp. 37-57, 2010, DOI:10.3970/sl.2010.003.037
Abstract Damage tolerance analysis is essential for evaluating life extension of aged structures which are in service beyond originally stipulated life. The major issue for such an analysis for aged aero-engines is the effect of multiple threedimensional flaws on the structural integrity. In this paper, an improved modified virtual crack closure integral technique is applied to investigate the interaction of twin coplanar semi-elliptical cracks in a finite body under both tension and bending. The specific configuration analysed and presented here is two semi-elliptical surface cracks for combinations of various aspect ratios, thickness ratios and combination of interspacing. The interaction effects are… More >

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S. K. Patel¹, B. Dattaguru², K. Ramachandra³
Structural Longevity, Vol.3, No.1, pp. 59-86, 2010, DOI:10.3970/sl.2010.003.059
Abstract A crack growth model for multiple surface cracks has been proposed and used in the study of multiple interacting and coalescing semi-elliptical cracks. Using this crack growth model the effect of multi-site damage on residual life is studied in detail. The stress intensity factor, crack shape development and crack propagation life are discussed. Numerical predictions of crack propagation lives have been verified by an experiment crack growth study on specimens having coplanar multiple semi-elliptical cracks made of an aero-engine disk material. The crack shape evolution and life estimated from numerical methods are found to be in good agreement with the… More >

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