Correlating toughness and roughness in ductile fracture

Laurent Ponson (1) , Ankit Srivastava (2) , Shmulik Osovski (2) , Elisabeth Bouchaud (3) , Viggo Tvergaard (4) , Alan Needleman (2)

1 DALEMBERT - Institut Jean Le Rond d'Alembert
2 Department of Mechanical Engineering
3 Gulliver (UMR 7083)
4 DTU - Danmarks Tekniske Universitet = Technical University of Denmark

Three dimensional calculations of ductile crack growth under mode I plane strain, small scale yielding conditions are carried out using an elastic-viscoplastic constitutive relation for a progres- sively cavitating plastic solid with two populations of void nucleating second phase particles. Full field solutions are obtained for three dimensional material microstructures characterized by ran- dom distributions of void nucleating particles. Crack growth resistance curves and fracture surface roughness statistics are calculated using standard procedures. The range of void nucleating particle volume fractions considered give rise to values of toughness, JIC , that vary by a factor of four. For all volume fractions considered, the computed fracture surfaces are self-affine over a size range of about two orders of magnitude with a roughness exponent of 0.54 ± 0.03. For small void nucleating particle volume fractions, the mean large particle spacing serves as a single dominant length scale. In this regime, the correlation length of the fracture surface corresponding to the cut-off of the self-affine behavior is found to be linearly related to JIC thus quantitatively correlating toughness and fracture surface roughness.

Mots clés: Ductile fracture; toughness; roughness

Domaines: Mécanique statistique [cond-mat.stat-mech]; Mécanique des solides [physics.class-ph]; Mécanique des solides [physics.class-ph]

Laurent Ponson, Ankit Srivastava, Shmulik Osovski, Elisabeth Bouchaud, Viggo Tvergaard, et al.. Correlating toughness and roughness in ductile fracture. 2013. ⟨hal-00845351⟩