Ductile fracture by cavity nucleation between larger voids

Abstract A mechanism of ductile fracture involving the interaction of relatively large voids with small-scale voids is studied by a computational model. The larger voids are described as circular cylindrical holes arranged in a doubly periodic array in the initial state. In the matrix material between these voids the nucleation and growth of much smaller voids is accounted for by using approximate constitutive equations for a ductile, porous medium. The computations show bands of highly localized straining and void growth, initiating at the surfaces of larger voids and growing into the matrix material, until the bands connect two neighbouring voids. The materials are analysed both under plane strain conditions and under conditions approximating those in a round tensile bar. The failure strains obtained under different principal stress ratios show rather good agreement when plotted against a measure of the stress-triaxiality.

[1]  A. Needleman,et al.  Void Nucleation Effects in Biaxially Stretched Sheets , 1980 .

[2]  G. T. Hahn,et al.  Metallurgical factors affecting fracture toughness of aluminum alloys , 1975 .

[3]  J. Rice,et al.  CONDITIONS FOR THE LOCALIZATION OF DEFORMATION IN PRESSURE-SENSITIVE DILATANT MATERIALS , 1975 .

[4]  F. A. McClintock,et al.  A Criterion for Ductile Fracture by the Growth of Holes , 1968 .

[5]  R. Hill,et al.  XLVI. A theory of the plastic distortion of a polycrystalline aggregate under combined stresses. , 1951 .

[6]  J. Hutchinson,et al.  Shear band formation in plane strain , 1981 .

[7]  D. M. Tracey,et al.  On the ductile enlargement of voids in triaxial stress fields , 1969 .

[8]  A. Gurson.  Continuum Theory of Ductile Rupture by Void Nucleation and Growth: Part I—Yield Criteria and Flow Rules for Porous Ductile Media , 1977 .

[9]  A. Needleman.  Void Growth in an Elastic-Plastic Medium , 1972 .

[10]  V. Tvergaard.  Influence of voids on shear band instabilities under plane strain conditions , 1981 .

[11]  S. H. Goods,et al.  Overview No. 1: The nucleation of cavities by plastic deformation , 1979 .

[12]  Alan Needleman,et al.  Void nucleation effects on shear localization in porous plastic solids , 1982 .

[13]  R. H. Stone,et al.  Discussion of “metallurgical factors affecting fracture toughness of aluminum alloys” , 1975 .

[14]  J. Gurland,et al.  Observations on the fracture of cementite particles in a spheroidized 1.05% c steel deformed at room temperature , 1972 .

[15]  J. Hancock,et al.  On the mechanisms of ductile failure in high-strength steels subjected to multi-axial stress-states , 1976 .

[16]  A. C. Mackenzie,et al.  On the influence of state of stress on ductile failure initiation in high strength steels , 1977 .

[17]  Viggo Tvergaard,et al.  Flow Localization in the Plane Strain Tensile Test , 1981 .

[18]  Yamamoto Hiroyasu,et al.  Conditions for shear localization in the ductile fracture of void-containing materials , 1978 .

[19]  J. Im,et al.  Cavity formation from inclusions in ductile fracture , 1975 .

[20]  V. Tvergaard.  On localization in ductile materials containing spherical voids , 1982, International Journal of Fracture.