Size-Effects at a Crack-Tip Interacting with a Number of Voids

Viggo Tvergaard (1) , Christian F. Niordson (2)

1 DTU - Danmarks Tekniske Universitet = Technical University of Denmark
2 Department of Mechanical Engineering, Solid Mechanics

ABSTRACT – A strain gradient plasticity theory is used to analyze the growth of discretely represented voids in front of a blunting crack-tip, in order to study the influence of size-effects on two competing mechanisms of crack growth. For a very small void volume fraction the crack-tip tends to interact with one void at a time, while larger void volume fractions lead to simultaneous interaction of multiple voids on the plane ahead of the crack-tip. The present computations are stopped before coalescence of the nearest void with the crack-tip. Analyses are carried out for different values of the characteristic material length relative to the initial void radius. For a case showing the multiple void mechanism it is found that the effect of the material length can change the behaviour towards the void by void mechanism. A material model with three characteristic length scales is compared with a one length scale model and the differences are discussed.

Mots clés: Physical Sciences

Viggo Tvergaard, Christian F. Niordson. Size-Effects at a Crack-Tip Interacting with a Number of Voids. Philosophical Magazine, 2009, 88 (30-32), pp.3827-3840. ⟨10.1080/14786430802225540⟩. ⟨hal-00513908⟩