Open Access3D Analyses of crack propagation in torsion
Author(s) -
D Shiozawa,
Serrano Munoz,
Sylvain Dancette,
Catherine Verdu,
Joël Lachambre,
Jy Buffière
Publication year - 2015
Publication title -
frattura ed integrità strutturale
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.368
H-Index - 19
ISSN - 1971-8993
DOI - 10.3221/igf-esis.33.07
Subject(s) - perpendicular , materials science , torsion (gastropod) , fracture mechanics , grain boundary , slip (aerodynamics) , alloy , grain size , crack closure , composite material , structural engineering , finite element method , crystallography , geometry , engineering , microstructure , chemistry , medicine , mathematics , surgery , aerospace engineering
The initiation and propagation of fatigue cracks during cyclic torsion loading was studied in a cast\udAl alloy (A357) with a relatively large (~500 μm) grain size. 2D observations, revealed that multi site crack\udinitiation occur on the {111} slip planes exhibiting the highest slip activity (iso-strain Taylor analysis),\udpreferentially on planes nearly perpendicular to the sample axis. Within the first grain, the cracks have a\udpronounced crystallographic propagation mode (mode II crack growth) and strongly interact with the grain\udboundaries. In situ 3D monitoring of torsion fatigue tests using synchrotron X-ray tomography reveal that\udpropagation towards the interior of the samples occurs first along the sample periphery in mode II leading to\udrelatively shallow cracks which penetrate towards the sample center only after a large number of cycles is\udreached .The values of mode I, II and III stress intensity factors have been calculated from finite element\udsimulation at the tip of the shallow mode II crack. Those values are used to analyse the bulk propagation of the\udobserved cracks