Zencrack has an interface to Ansys/Mechanical APDL. A brief overview of the interface is given below.

The interface to Ansys works via Ansys batch files:

• An uncracked mesh must be supplied as an Ansys batch file. This can be created in Workbench, APDL or a third party pre-processor.
• Zencrack then combines the uncracked mesh with data in the Zencrack input file to create a batch file for the cracked component.
• The cracked mesh is submitted for analysis by Ansys.
• When the Ansys analysis is completed, Zencrack extracts results directly from files created during the Ansys analysis - these files are generated via output requests that were created in the cracked mesh batch file.

If crack growth is required, Zencrack carries out crack advancement using the results of the Ansys analysis and generates a new batch file for an advanced crack position. The new cracked mesh is then submitted for analysis. This process is shown schematically in the Zencrack flowchart.

This interface is able to calculate the following fracture mechanics parameters at nodes along the crack front:

• J-integrals via the Ansys CINT, TYPE, JINT option.
• SIF-integrals via the Ansys CINT, TYPE, SIFS option.
• T-stresses via the CINT, TYPE, TSTRESS option.
• Ct-integral via the Ansys CINT, TYPE, CSTAR option in a creep analysis.
• The stress intensity factors K_I, K_II and K_III calculated from nodal displacements (linear elastic isotropic materials).

The default analysis settings are to calculate j-integrals and displacement based stress intensity factors with the j-integral values used to drive crack growth. These defaults can be modified in the input file for a particular analysis.

The analysis results may be post-processed using the Zencrack GUI or utility programs provided with Zencrack. These allow visualisation of crack growth profiles, xy plotting and generation of .csv files for use in a spreadsheet. In addition, all of the standard Ansys output files are available for post-processing e.g. the .db file. During a crack growth analysis, the standard Ansys files can be saved after successive Ansys analyses to allow subsequent post-processing of multiple crack positions.