Summary for version 7.4

General

• The crack-block library has been revised to group crack-blocks into "families" and eight new crack-blocks are provided.
• There is no longer any restriction on model size subject to available memory and some formatting restrictions.
• There is no longer any restriction on the number of split pairs in an element split set subject to available memory.
• A number of algorithms have been improved to provide performance enhancements particularly on large jobs with highly irregular / non-consecutive node and element numbers and jobs with a large number of elements in the relax element list.
• A new SURROUND FIX algorithm for fixing up the elements surrounding the crack blocks has been developed to help reduce element distortion.
• A new SPLINE FIXUP algorithm distributes the crack front nodes evenly along the crack front. This is of greatest use for through cracks growing in sections with changing thickness or high curvature.
• The algorithm that controls transfer of crack-blocks to a new location has been improved.
• The number of contour rings that can be processed has been increased to accommodate the largest available crack-blocks.
• The direction for crack growth prediction that is calculated from stress intensity factors now uses the maximum tangential stress criterion rather than the inverse tangent criteria that was used in previous releases.
• The direction for crack growth can be specified using energy or displacement based results independently of the method used for calculating the magnitude of crack growth.
• A capability is added to allow remote execution of the finite element code on a Unix machine when Zencrack is installed on a Windows machine.
• If the output filename for a job is not specified in the input file, a default string is added to the zcr filename. This string can now be defined by the user.

Abaqus interface

• The handling of element and node sets has been improved to allow the use of set names in defining boundary conditions, loads and surfaces. This significantly reduces the manual effort in preparing the uncracked mesh.
• Degrees of freedom 1-16 and special types XSYMM, YSYMM, ZSYMM, XASYMM, YASYMM, ZASYMM, ENCASTRE, PINNED are now handled for possible updates in the crack region on *BOUNDARY.
• Every *BOUNDARY option is now processed independently for possible updates.
• The update of the Abaqus *SURFACE option for crack faces and the use of the Zencrack CONTACT keyword have been modified to give increased functionality.
• New parameters K FACTORS and T-STRESS are available on the *ENERGY RELEASE RATE keyword. These options insert additional contour integral requests for K values and T-stresses into the cracked mesh. The results of these evaluations are not currently processed by Zencrack but are available in the Abaqus .dat files for review or manual processing.

Ansys interface

• Every group of consecutive D options is treated as a single independent block for possible updates.
• Degrees of freedom XROT, YROT, ZROT and TEMP on D options are now handled for updates in addition to UX, UY, UZ, ALL.
• The file type .out is added to the possible Ansys files that can be saved via the *SAVE option.

Finas interface

• This is a new interface in this release.

Marc interface

• All DIST LOADS options before and after END OPTION are now considered for updating by Zencrack.
• Every FIXED DISP model definition option is now processed independently for possible updates.
• Every DISP CHANGE history option is now processed independently for possible updates.
• The interpolation of nodal temperatures into the crack-blocks from the values in the uncracked mesh is now available in the Marc interface. Temperature distributions on the following options can be updated: FIXED TEMPERATURE, INITIAL TEMP, POINT TEMP and TEMP CHANGE.