Finite element interface to Ansys

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

• An uncracked mesh must be supplied as an Ansys batch file.
• 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 provide the following fracture mechinics parameters after processing the results from an Ansys analysis:

• The magnitude and direction of the maximum energy release rate, G, at each node along the crack front.
• Calculated via data from the Ansys CINT option.
• For non-linear analysis this term is J, though it is processed in the same way by Zencrack.
• This is available for Ansys 11.0SP1 or later.
• The stress intensity factors K_I, K_II and K_III at each node along the crack front.
• Calculated from nodal displacements.
• Direction for crack growth is calculated from Ks.
• The stress intensity factors are also converted into an equivalent energy term.
• Equations used are only valid for linear elastic isotropic materials.

The analysis results may be post-processed using the utility programs provided with Zencrack. These allow generation of a .csv file for use in a spreadsheet and the creation of crack growth profile representations for crack growth analyses. 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.

Ansys is a trademark of SAS IP, Inc., a wholly owned subsidiary of Ansys Inc., Canonsburg, Pennsylvania, U.S.A.
http://www.ansys.com