The main update in version 9.4 is the ability to merge multiple crack remesh regions into one. This improves the analysis of interactions between different cracks compared to previous versions. For models using the remesh method for crack growth, the crack surface area can now be viewed not only in the .rep file but also plotted in the x-y plot post-processing function. Remesh regions can now include degenerate hexahedral elements. The GUI encoding has been upgraded to better handle files containing non-ASCII characters.
In previous versions, the remesh regions for different cracks in a model could not overlap or intersect. In version 9.4, when remesh regions for different cracks contact or intersect, they are automatically merged into a new region. The merging process is fully automatic, requiring no additional input from the user.
Modeling cracks close to each other is now easier, such as two cracks on a symmetry plane of a welded pipe, as shown in Figure 1. Similarly, modeling the interaction or shielding effects between cracks, such as three co-planar cracks sharing one remesh region, becomes simpler (Figure 2)
When cracks that initially have separate remesh regions eventually intersect during crack growth, their remesh regions will also be merged automatically.
In version 9.4-1, the crack surface area for the remesh model is calculated and written to the .rep file. It is also added to the list of variables for plotting in the GUI, allowing users to plot crack surface area curves. The crack surface area is the sum of the areas of all the elements on one side of the crack surface.
Unlike previous versions, version 9.4 allows remesh regions to be fully contained within degenerate hexahedral elements.
Version 9.4-1 includes more checks for tetrahedral element quality during remeshing to avoid generating poor-quality elements. The checking criteria have been aligned more closely with Abaqus and Ansys. In previous versions, only a zero-volume check for Abaqus was performed, but now additional checks have been introduced:
In version 9.3, multiple cracks were defined as one surface. In version 9.4, each crack can have its own crack surface, allowing different conditions such as pressure and heat transfer to be applied to different cracks.
The GUI in version 9.4-1 introduces the ability to display degenerate elements.
Version 9.4-1 changes the way crack front node coordinates are extracted and reported by the process program. The node coordinates are now extracted after crack growth integration and redistribution to ensure consistency with the geometric model, addressing an issue in previous versions where node coordinates might fall outside the geometric model (see Figure 6).
Version 9.4-1 introduces two options for defining the sum of da:
The example in Figure 6 illustrates the potential differences that may arise between the two different definitions in extreme cases.
In version 9.4-1, a new variable, "Distance along coordinate path," was introduced. This variable calculates the accumulated distance of a specific node along the continuous crack front position, similar to the "Sum of da (from f.e. analysis profile points)."
The “local zencrack_gui.ini” file was first introduced in version 9.2-2, and in version 9.4-1, its functionality has been expanded to control remeshing in command-line environments as follows:
Ansys 2024R1 changes the handling of over-constrained models, potentially introducing stress hotspots near boundary conditions, an issue not present in previous versions. Version 9.4-1 addresses this issue to ensure that over-constraint does not occur when using the Ansys 2024R1 interface.
In 2024R1, there is a change in how over-constraints are handled. Testing has revealed that hot spots of stress can occur at tie constraints near boundary conditions, which were not present in earlier versions.
Version 9.4-1 addresses this issue to ensure that over-constraints do not occur. However, if using older versions of Zencrack, caution is advised when using the Ansys 2024R1 interface.
RLM installation now allows for the creation of a Windows service to run the license server.
The output_code.dat file has been updated with new variable definitions and support for the reduced variable axis list in the GUI. Additionally, some variable names have been changed:
Additionally, several other modifications have been made to change the curve plotting functionality in the GUI:
The subroutine user_dadn_sif has been updated to allow the sif-integral parameter as an input.
Additionally, the Ini file has introduced new entries:
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