*Int.J.Fract.* **148**(3), 205-219, 2007

### NUMERICAL SIMULATIONS OF VOID LINKAGE IN MODEL MATERIALS USING
A NONLOCAL DUCTILE DAMAGE APPROXIMATION

A. Weck¹, J. Segurado² J. LLorca²,
D. Wilkinsion¹, H.J. Böhm³

¹Department of Science and Engineering

McMaster University, Hamilton, ON, Canada

²Departamento de Ciencia de Materiales

Universidad Politécnica de Madrid, Madrid, Spain

³Institute of Lightweight Design and Structural
Biomechanics,

TU Wien, Vienna, Austria

**Abstract** -
Experiments on the growth and linkage of 10 µm diameter holes laser drilled in
high precision patterns into Al-plates were modelled with finite elements.
The simulations used geometries identical to those of the experiments and
incorporated ductile damage by element removal under the control of a ductile
damage indicator based on the micromechanical studies of Rice and Tracey.
A regularization of the problem was achieved through an integral-type nonlocal
model based on the smoothing of the rate of a damage indicator D over a
characteristic length L. The simulation does not predict the experimentally
observed damage acceleration either in the case where no damage is included or
when only a local damage model is used.
However, the full three-dimensional simulations based on the nonlocal damage
methodology do predict both the failure path and the failure strain at void
linkage for almost all configurations studied.
For the cases considered the critical parameter controlling the local
deformations at void linkage was found to be the ratio between hole diameter
and hole spacing.

(hjb,080520)