caa a22 4500 46574057X CHVBK 20180323111808.0 cr unu---uuuuu 170327e19900701xx s 000 0 eng 10.1007/BF00047062 doi (NATIONALLICENCE)springer-10.1007/BF00047062 Ravichandran K. Department of Metallurgy, Indian Institute of Science, 560 012, Bangalore, India aut A theoretical model for roughness induced crack closure [Elektronische Daten] [K. Ravichandran] A theoretical model for the effects of grain size on the magnitude of roughness induced crack closure (RICC) at fatigue crack growth threshold has been proposed. With the basic configuration of a crack propagating incrementally along planar slip bands and deflecting at grain boundaries, an idealized zig-zag crack path is considered. The effective slip band length is considered to be equal to grain size. It is assumed that the dislocations emitted from the crack tip upon loading to form the pile-up are completely irreversible to produce a comnined mode I and mode II displacement at the crack tip. The assumption of continuously distributed dislocations in the pile-up facilitated the calculation of crack tip sliding displacement (CTSD) along the slip plane from which the mode I closure disregistry just behind the crack tip can be calculated. The closure stress intensity factor at threshold, K el,th could then be expressed as a function of critical resolved shear stress, average macroscopic yield stress, angle subtended by the slip plane with the crack plane and the length of the slip band. Comparisons of the predicted trends with experimental data from various alloy systems indicate good agreement. Kluwer Academic Publishers, 1990 International Journal of Fracture Kluwer Academic Publishers 44/2(1990-07-01), 97-110 0376-9429 44:2<97 1990 44 10704 https://doi.org/10.1007/BF00047062 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00047062 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Ravichandran K. Department of Metallurgy, Indian Institute of Science, 560 012, Bangalore, India aut NATIONALLICENCE 773 0- International Journal of Fracture Kluwer Academic Publishers 44/2(1990-07-01), 97-110 0376-9429 44:2<97 1990 44 10704 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer