Research

Meshfree modelling of three dimensional fracture with distance fields

Principal investigator:
Co-investigator(s): N. Petrinic (Oxford)

Predicted crack surface for a skew crack propagated under torsional loadingModelling fracture with traditional finite element techniques could be a very burdensome task, even with few cracks: with just two interacting cracks, it is necessary to re-mesh over very small portions of space, causing crashing of even the most sophisticated mesh generators.
When cracks grow in number, this task in 3D borders the impossible.

The aim is to eliminate the burden of remeshing for modelling fractures in real three- dimensional engineering components and/or scenarios. Meshfree methods (and a new devised intrinsic enrichment based on distance fields) offer the possibility of simulating with ease multiple interacting multi-faceted non-planar cracks in 3D.

Shear stress and deformed configurationThe concept is based on distance fields: scalar functions defi ning the minimum distance of a given point in the space from the boundary of an object. Crack surfaces are geometric entities whose shapes can be arbitrary, The derivatives of distance functions for such surfaces are discontinuous across the surface, and continuous all around the edges, making them the perfect candidate for enriching the displacement variable.

The incremental nature of the developed approach does not require re-computation of the enrichment for the entire crack surface as advancing crack front extends incrementally as a set of connected surface facets. The concept is based on purely geometric representation of discontinuities thus addressing only the kinematic aspects of the problem, such to allow for any constitutive and cohesive interface models to be used.