CGROW

CGROW, Action, Par1, Par2
Defines crack-growth information

Compatible Products: – | – | – | Enterprise | Ent PP | Ent Solver | –

Action

Specifies the action for defining or manipulating crack-growth data:

NEW

 — 

Initiate a new set of crack-growth simulation data (default).

CID

 — 

Specify the crack-calculation (CINT) ID for energy-release rates to be used in the fracture criterion calculation.

FCOPTION

 — 

Specify the fracture criterion for crack-growth/delamination.

CPATH

 — 

Specify the element component for crack growth.

DTIME

 — 

Specify the initial time step for crack growth.

DTMIN

 — 

Specify the minimum time step for crack growth.

DTMAX

 — 

Specify the maximum time step for crack growth.

FCRAT

 — 

Fracture criterion ratio (fc).

STOP

 — 

Stops the analysis when the specified maximum crack extension is reached.

METHOD

 — 

Define the method of crack propagation.

FCG

 — 

Specifies fatigue crack growth.

Command Specification for Action = NEW

CGROW, NEW, Par1

Par1 --

Crack-growth data set ID (integer value).

Command Specification for Action = CID

CGROW, CID, Par1

Par1 --

Contour-integral calculation (CINT) ID for energy-release rates to be used in fracture criterion calculation.

Command Specification for Action = FCOPTION

CGROW, FCOPTION, Par1, Par2

Par1 --

MTAB -- Crack-growth fracture criterion used with the material data table (TB,CGCR).

GTC -- Define the critical energy-release rate, a simple fracture criterion.

Par2 --

Material ID for the material data table, if Par1 = MTAB.

The critical energy-release rate value, if Par1 = GTC.

Command Specification for Action = CPATH

CGROW, CPATH, Par1

Par1 --

Interface element component for crack path.

Command Specification for Action = DTIME

CGROW, DTIME, Par1

Par1 --

Initial time step when crack growth is detected.

Command Specification for Action = DTMIN

CGROW, DTMIN, Par1

Par1 --

Minimum time step allowed when crack growth is detected.

Command Specification for Action = DTMAX

CGROW, DTMAX, Par1

Par1 --

Maximum time step allowed when crack growth is detected.

Command Specification for Action = FCRAT

CGROW, FCRAT, Par1

Par1 --

Fracture criterion ratio (fc, where fc is generally around 1). The recommended ratio is 0.95 to 1.05. The default is 1.00.

Command Specification for Action = STOP

CGROW, STOP, Par1

Par1 --

CEMX -- Stops the analysis when the crack extension for any crack front node reaches the maximum value (specified via Par2).

Par2 --

Value of maximum crack extension allowed.

Command Specification for Action = METHOD

CGROW, METHOD, Par1

Par1 --

VCCT -- Use VCCT to grow the crack (default).

XFEM -- Use XFEM to grow the crack.

Command Specification for Action = FCG

CGROW, FCG, Par1,Par2

Par1 --

METH -- Fatigue crack-growth method.

DAMX -- Maximum crack-growth increment.

DAMN -- Minimum crack-growth increment.

SRAT -- Stress/load ratio.

DKMIN -- Threshold value of equivalent stress-intensity factor (SIF).

DN -- Incremental number of cycles.

Par2 --

Method -- LC (life-cycle method) or CBC (cycle-by-cycle method). Valid only when Par1 = METH.

VALUE -- Value for the specified Par1. Valid only when Par1 = DAMX, DAMN, SRAT, DKMIN, or DN.

Notes

When Action = NEW, the CGROW command initializes a crack-growth simulation set. Subsequent CGROW commands define the parameters necessary for the simulation.

For multiple cracks, issue multiple CGROW,NEW commands (and any subsequent CGROW commands necessary to define the parameters) for each crack.

If the analysis is restarted (ANTYPE,,RESTART), the CGROW command must be re-issued.

For VCCT crack growth:

  • Crack-growth element components must use the crack tip nodes as the starting nodes of the crack path.

  • Fracture criteria (Action = FCOPTION) use energy-release rates calculated via VCCT technology (CINT,TYPE,VCCT). For information about the fracture criteria available, see Fracture Criteria in the Fracture Analysis Guide or the documentation for the TB,CGCR command.

For XFEM-based crack growth:

  • When using XFEM to grow the crack (CGROW,METHOD,XFEM), the crack specification originates via the XFENRICH and XFDATA commands.

  • In an XFEM-based crack growth analysis, Action = CPATH, DTMIN, or DTMAX have no effect.

  • Action = STOP affects XFEM-based fatigue crack growth only.

If the SAVE command is issued after any CGROW commands are issued, the CGROW commands are not saved to the database. Reissue the CGROW command(s) when the database is resumed.

Menu Paths

This command cannot be accessed from a menu.

Release 18.2 - © ANSYS, Inc. All rights reserved.