Comparative Analysis of Nonlocal Approaches for Modeling Ductile Fracture

COMPLAS 2025 - 18th International Conference on Computational Plasticity, Barcelona, İspanya, 2 - 05 Eylül 2025, (Yayınlanmadı)

The localization of the strain is the precursor to the initiation of damage and the propagation

of cracks in ductile materials. In the numerical analysis of ductile fracture, the size of the localized

damaged region is directly influenced by the spatial resolution of the discretization of

the finite element (FE) when a local coupled damage model is used. As a result, an inherent

sensitivity to the mesh resolution is observed due to the governing equations losing ellipticity

in the softening regime. To overcome this issue, nonlocal frameworks have been developed

and extensively studied in the literature [1]. Numerous attempts have been made to achieve

nonlocality within existing coupled ductile damage and fracture frameworks [2]. In this study,

two widely popular approaches present in the literature are implemented via user subroutines in

Abaqus and compared to achieve mesh objectivity. The nonlocal counterpart of a local variable

is computed using two different strategies. The first one is performed through an averaging

scheme after each solution increment to non-localize equivalent plastic strain or the damage

variable. The second approach involves solving a Helmholtz-type equation using built-in coupled

temperature-displacement elements employing the analogy to the steady-state heat transfer

equation. Then these two approaches are compared in terms of performance in achieving meshindependent

solutions.

REFERENCES

[1] Peerlings R.H.J., Geers M.G.D., de Borst R., BrekelmansW.A.M., A critical comparison of nonlocal

and gradient-enhanced softening continua. International Journal of Solids and Structures , Vol.

38, pp. 7723–7746, 2001.

[2] Bergo S., Morin D., Hopperstad O.S., Accurate modelling of the elastic behavior of a continuum

with the discrete element method. International Journal of Solids and Structures, Vol. 219, pp. 134–

150, 2021.