A. Needleman et V. Tvergaard, DYNAMIC CRACK-GROWTH IN A NONLOCAL PROGRESSIVELY CAVITATING SOLID, European journal of mechanics. A, Solids, 17(3), 1998, pp. 421-438
Dynamic crack growth is analyzed numerically using a nonlocal constitu
tive formulation for a porous ductile material. The delocalization rel
ates to the void growth and coalescence mechanism and is incorporated
in terms of an integral condition on the rate of increase of the void
volume fraction. The material is modeled as elastic-viscoplastic with
the thermal softening due to adiabatic heating accounted for. Finite e
lement computations are carried our for edge cracked specimens subject
to tensile impact loading. Two values of the material characteristic
length and two finite-element discretizations are used in most computa
tions. The effect of the material characteristic length on the crack g
rowth behavior and on the mesh sensitivity of the results is considere
d. For comparison purposes, results are also obtained For the correspo
nding local constitutive relation. The crack growth resistance is foun
d to increase and the crack speed to decrease with increasing values o
f the material characteristic length. The crack growth predictions usi
ng the nonlocal constitutive model exhibit less mesh sensitivity than
the corresponding ones based on the local constitutive relation. Howev
er, for the largest value of the material characteristic length consid
ered a divergence between predictions based on three discretizations i
s found at late times. (C) Elsevier, Paris.