Software > Zencrack > Overview > Under development

Under development

Development work in Zencrack

  • New re-meshing capability for mesh independent crack insertion into an uncracked mesh:
    • geometric definition of an initial crack, independent of the underlying mesh
    • remeshing of underlying hex or tet meshes to introduce the crack
    • crack at a symmetry plane, surface breaking or fully embedded
    • initial crack shape straight or elliptic
    • rings of hex elements at the crack front with mesh density controlled by the user
    • tet mesh surrounding the rings
    • fully automatic definition of the extent of the remeshed tet region and mesh density within that region (with manual control if desired)
    • update of displacement boundary conditions, pressure loads, surface definitions and temperatures in the remesh region
    • the above are functional developments, additional features are in progress
  • Implementation of a non-linear Kujawski-Ellyin crack growth law. ✔
    • Ref: M.Lepore, F.Berto, D.Kujawski, Non-linear models for assessing the fatigue crack behaviour under cyclic biaxial loading in a cruciform specimen, Theoretical and Applied Fracture Mechanics, Volume 100, 14-26, April 2019.
  • Implementation of crack growth direction from stress intensity factors based on the work of Richard et al. ✔
    • Ref: H.A.Richard, M.Fulland, M.Sander, Theoretical crack path prediction, Fatigue Fract Engng Mater Struct 28, 3-12, 2005.
  • Extension of the processing available for interaction integrals to allow them to be used to drive a crack growth analysis ✔.
  • Support for the Ansys option for specifying the auxiliary field solution when calculating interaction integrals: mixed, plane stress or plane strain. ✔
  • Re-working of some of the options on the *ENERGY RELEASE RATE keyword to accommodate some of the above changes and to allow future additions. ✔
  • Creation of an output set of crack-blocks that are "ready to transfer". ✔

Examples of re-meshing - input definition and preview

Examples of Zencrack GUI input screens to define input data for remeshing. Click thumbmails for full size image.

Definition of elliptic crack position plus ring preview

Definition of elliptic crack position plus ring preview

Ring elements and remesh region preview

Ring elements and remesh region preview

Remeshed region preview

Remeshed region preview

Completed mesh with elliptic crack

Completed mesh with elliptic crack

Examples of re-meshing - crack growth

Two examples of "single analysis" crack growth prediction. Click thumbmails for full size image.

Uncracked mesh
Cracked region with displacement after some crack growth
Remeshing during crack growth
Remeshing during crack growth
Crack profiles

Semi-elliptic starter crack in test specimen under bending

Uncracked mesh
Cracked region with displacement after some crack growth
Remeshing during crack growth
Remeshing during crack growth
Crack profiles

Circular corner crack in connecting rod

Development work in the Zencrack GUI

  • New input, preview and display options to support the new re-meshing capability for crack insertion into an uncracked mesh (see additional examples below - click thumbmail for full size image). ✔
  • Re-working of the Energy Release Rate screen to accommodate the changes described above. ✔
  • Improved performance for large meshes (faster import and manipulation). ✔
  • Import and optional display of the material regions defined in a mesh. ✔
  • Identification of disconnected mesh regions. ✔
  • Labelling of profiles when displaying crack growth profile results. ✔
  • Labelling of splines (Input Tab crack front splines and Display Tab splines). ✔
  • Ability to add multiple meshes into one viewport. ✔
  • Ability to display some types of surface definitions. ✔

Additional re-meshing examples

Placement of crack into a specific region

Placement of crack into a specific region

Preview of crack front nodes with crack in a specifed region

Preview of crack front nodes; crack in a specifed region

Connecting rod, crack definition and remeshed region

Connecting rod, crack definition and remeshed region

Bracket, crack definition and remeshed region

Bracket, crack definition and remeshed region

Disk, crack definition and remeshed region

Disk, crack definition and remeshed region

Disk, larger crack size

Disk, larger crack size

Threaded connection, crack definition and remesh region

Threaded connection, crack definition and
remesh region

Threaded connection, confirmation of symmetry plane boundary condition updates and contact surface update

Threaded connection, confirmation of boundary condition updates and contact surface update (in Abaqus/Viewer)