Contact Correction
The Contact Correction app adjusts grain-to-grain contacts to reflect their true mechanical behavior by reducing stiffness using one of two methods. Both approaches rely on the GrainFind watershed-based grain segmentation, which accurately identifies grains and their contact zones.
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Modules needed to run this GeoApp:
GrainFind, MatDict
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Click Edit to open the Contact Correction parameter dialog.
Select a Result File Name fitting to the current project.
Define the Reconnect Fragmented Grains - Interface Threshold value. This value determines the number of touching grain fragments that are merged. A value of 0% causes all touching grains to be merged, while a value of 100% causes no merging at all. Refer to GrainFind to find more information on this parameter.
Then select the Contact Correction Method. Here two methods are available:
Area-Dependent
The Area-Dependent Stiffness Reduction is described in detail in Halisch et al. (2025). This method keeps the original grain contact segmentation unchanged, but modifies the mechanical properties to obtain a realistic behavior by reducing the effective stiffness based on the relative size of the contact areas between grains.
When you select this method, you need to define the Reduce Contact Properties by value. This percentage determines the reducing factor for the density, Young's modulus, and Poisson's ratio.
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Explicit
When using the Explicit Contact Area Reduction (Saxena et al., 2019), contact voxels are physically eroded to shrink contact zones. This method affects the porosity of the original structure, resulting in simulations that better match experimental conditions, even when working with resolution-limited imaging data.
When you select this method, you need to define the Eroded Voxel Number. This parameter controls the layer size of voxels by which contact zones between grains and pore space are eroded. Refer to ProcessGeo to find more information on eroding voxels.
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After defining all parameters click OK to close the dialog, go back to the GeoApp section, and click Run.
Results
Below the results from both methods are shown for an exemplary anode structure using the default settings.
Area-Dependent
After the Contact Correction app finishes the result file is loaded in the Result Viewer. The result file states the input parameters and under the Data Visualization tab you can load the contact-corrected structure. This structure is also automatically loaded in the visualization area at the end of the run.
In the contact-corrected structure each contact area has an individual material ID and individual mechanical properties that are based on its relative size. You can see the individual material properties in the material name or by viewing the Constituent Materials.
In the result folder, you find additional results (e.g., Identify Grains) as well as the original and contact-corrected structures. Additionally, structures containing only the contact areas, or solely with simple and weak contacts are available for loading.
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Explicit
After the Contact Correction app finishes the result file is loaded in the Result Viewer. The result file states the input parameters and under the Data Visualization tab you can load the contact-corrected structure. This structure is also automatically loaded in the visualization area at the end of the run. Additionally, the identified grain contacts are loaded as a volume field.
In the contact-corrected structure all identified and then eroded contact areas are assigned to a new material ID. This materials has identical mechanical properties as the original material but the area has been reduced by the set number of voxels.
In the result folder, you find additional results (e.g., Identify Grains, or Percolation Path) as well as the original and contact-corrected structures. Additionally, structures containing only the contact areas, or solely with simple and weak contacts are available for loading.
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