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NewCrack Command

The NewCrack command together with subsequent GrowCrack, GrowCrackLine, GrowCrackArc, and CrackThickness commands are used to define cracks in an MPM problem (see the OSUPDocs wiki for more details on defining cracks). A crack definition is started with a NewCrack command, which is followed by one or more of the other commands to complete the crack definition

NewCrack (x1),(y1),<(mat)>,<(lawid)>,<(tract)>
GrowCrack (x2),(y2),<(mat)>
GrowCrackLine (x2),(y2),(segs),<(mat)>,<(tract)>
GrowCrackArc (x1),(y1),(x2),(y2),(segs),(ang1),(ang2),<(mat)>,<(tract)>
CrackThickness (thick)

where the NewCrack command defines the start of a new crack its are parameters:

Following the NewCrack command, there can be any number of growing commands. Some commands define shapes and the shapes are linked up to create the full crack. Other commands set crack properties. The options are listed below. See each command for details on the parameters

A deprecated CrackInterface command used to set custom imperfect interface properties. The setting is now done with the (lawid) parameter above.

Notes

  1. The crack tip material ID should specify the initial material. The calculations will automatically update the crack tip material ID if the crack propagates into a new material.
  2. There can be any number of cracks in an MPM analysis. Each NewCrack command will start a new crack. Subsequent GrowCrack, GrowCrackLine and GrowCrackArc commands add points to the current crack.
  3. Any crack that uses traction laws on any particles must be a frictionless contact crack. In the NewCrack command, you cannot set both non-zero friction and a traction law material. You could, however, set a friction coefficient in the NewCrack command and then use traction law materials in the subsequent GrowCrack, GrowCrackLine and GrowCrackArc commands. Such cracks will be automatically converted to frictionless contact cracks.
  4. Besides modeling cracks, explicit cracks can also model imperfect interfaces.
  5. The development of explicit cracks in MPM calculations is described in the CRAMP section of the references.
  6. The NewCrack command is only allowed for MPM analyses.