Mechanical APDL Structural Analysis Guide

Example 12.6: Power Law Criterion Input

g1c=10.0

g2c=20.0

g3c=25.0

n1=2

n2=2

n3=3

TB,CGCR,1,,,POWERLAW

TBDATA,1,g1c,g2c,g3c,n1,n2,n3

12.1.3.7. User-Defined Fracture Criterion

A custom fracture criterion that you define is expressed as:

= I II III T

where the fracture criterion is a function of the Mode I (GI), Mode II (GII), and Mode III (GIII) energy-release

rates, and the material constant(s). All values are input via the TBDATA command.

A subroutine that you provide is necessary. For more information, see the Programmer's Reference.

Following is an example subroutine defining a linear fracture criterion:

*deck,user_cgfcrit optimize

SUBROUTINE user_cgfcrit (cgi, cid, kct,

& nprop, prop, fcscl,

& var1, var2, var3, var4)

c*****************************************************************

c

c *** primary function:

c compute facture criterion for crack growth

c user fracture criterion example

c *** notice: this routine contains sasi confidential information ***

c

#include "impcom.inc"

#include "ansysdef.inc"

c

c input arguments

c ===============

c cgi (int,sc , in) CGROW set id

c cid (int,sc , in) CINT ID to be used

c kct (int,sc , in) Current crack tip node

c nprop (int,sc , in) number of properties

c prop (dp ,ar(*), in) property array

c

c Output arguments

c ===============

c fcscl (dp, sc , ou) fracture criterion

c a return value of one or bigger

c indicates fracture

c

c Misc. arguments

c ===============

c var1 ( , , ) not used

c var2 ( , , ) not used

c var3 ( , , ) not used

c var4 ( , , ) not used

c

c*****************************************************************

c

c *** subroutines/function

c *** get_cgfpar : API to access fracture data

c *** wrinqr : ansys standard io function

c ***

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

VCCT-Based Crack Growth Simulation