Within the options to specify the crack front the user has control over several aspects of the generated mesh. For example:

• The radial midside nodes in the crack front elements may be specified at the quarter-point position or the midside position (or anywhere in between).
• The crack front nodal positions may contain a single node or multiple nodes that can open up to simulate blunting.
• The element rings around the crack front may be biased towards the crack front or evenly spaced.
• The outer size of the element rings around the crack front can be controlled.

These options are easy to specify in the input file. For example, the combination of quarter-point nodes and a single node for each crack front nodal location, which is suitable for the r^-0.5 LEFM singularity, is the default option on the *TIP MODEL keyword:

*TIP MODEL, LEFM

The combination of midside nodes and multiple nodes at crack front nodal locations gives an r^-1 singularity and is more suited to EPFM. This is requested using:

*TIP MODEL, EPFM