Zencrack example patch repair - icon

Composite Patch Repair

Sample Applications

Composite Patch Repair

Effect of an adhesively bonded patch repair on crack growth

Fatigue crack growth behaviour of a cracked thick aluminium-alloy plate repaired with a bonded composite patch is shown in this example. This is a simple geometry but the crack growth analysis demonstrates how user subroutines in Zencrack and Abaqus can be used together to enhance the overall simulation capability:

  • The Zencrack analysis begins with an un-patched plate. The meshing method for the analysis uses the Zencrack large crack-block approach. The uncracked mesh of the plate contains only two elements - detail is introduced when those elements are replaced during the meshing process.
  • A Zencrack user subroutine monitors the crack growth and at a user specified condition (e.g. critical crack length) inserts a repair patch into the subsequent finite element analyses.
  • An Abaqus user subroutine can optionally be used to include a damage model in the adhesive layer between the plate and patch.

Additional information about the analysis methods is shown in the video in Figure 3.

Zencrack example patch repair - mesh

Figure 1 - Uncracked and cracked meshes (without patch) and uncracked mesh (with patch)

Zencrack example patch repair - animation

Figure 2 - Analysis starting without the patch and having automatic insertion of the patch when a user defined condition is reached (one half of the plate is removed to show the crack shape development)

Zencrack example patch repair - slideshow icon

Figure 3 - Additional details of patch repair analysis