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Overview

Under Development

The new remeshing capability in Zencrack 9.0-1 was an initial implementation onto which more capability has been added with the latest releases, 9.3-1 and 9.4-1, having the ability to cater for multiple remeshing cracks and merging of remeshed regions respectively.

Work continues to enhance the remeshing capabilities with the interface to Simcenter Nastran being upgraded to included support for remeshing.

The multi-crack remeshing capability in 9.3-1 included a limitation that the remeshing regions of the cracks do not touch or overlap. Removing this limitation was the main development activity for version 9.4-1 and a pre-cursor to further generalising the remeshing capability for multiple cracks in subsequent releases (for example, allowing an initial elliptic geometric definition to cut multiple crack fronts into a model). An example of an enhancement in the now-released version 9.4-1, in which two cracks whose remesh regions are initially separate become embedded in a single remesh region after some growth has taken place, is shown below.

Multiple crack fronts on the same crack plane

Example of an initial geometric ellipse cutting one crack plane and two crack fronts into a model to generate an initial 45 degree inclined crack

Dev remeshing multicrack on plane 01

Preview of the initial crack front rings and region to be remeshed (Zencrack GUI)

Dev remeshing multicrack on plane 02

Displaced plot of advanced crack positions during growth prediction (Abaqus/Viewer)

Remeshing with the Simcenter Nastran interface

Example of post-processing in Simcenter 3D Results Viewer using a step from a Zencrack crack growth run carried out with Simcenter Nastran

Dev remeshing nastran01
Dev remeshing nastran02

Remeshing with improved crack plane triangulation during a growth analysis

Retriangulation of the initial crack plane (i.e. at step 1 of the analysis) is now carried into subsequent steps

Dev remeshing retriangulation no 008 ellipse

Crack plane triangulation at analysis step 8 without the new retriangulation option

Dev remeshing retriangulation yes 008 ellipse

Crack plane triangulation at analysis step 8 with the new retriangulation option

Merging of remesh regions

Example of initially separate remesh regions merging as cracks grow towards one another. This feature is available in release version 9.4-1.

A non-linear Kujawski-Ellyin crack growth law will be implemented as per the publication:

  • Non-linear models for assessing the fatigue crack behaviour under cyclic biaxial loading in a cruciform specimen
    M.Lepore, F.Berto, D.Kujawski
    Theoretical and Applied Fracture Mechanics, Volume 100, 14-26, April 2019, DOI: 10.1016/j.tafmec.2018.12.008.

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