Mechanical APDL Structural Analysis Guide

local,n,0,,,,

NSEL,S,LOC,X,Xctip1

NSEL,R,LOC,Y,Yctip1

NSEL,R,LOC,Z,Zctip1

CM,CRACK_FRONT_NODE_CM1

NSEL,S,LOC,X,Xctip2

NSEL,R,LOC,Y,Yctip2

NSEL,R,LOC,Z,Zctip2

CM,CRACK_FRONT_NODE_CM2

NSEL,S,LOC,X,Xctipn

NSEL,R,LOC,Y,Yctipn

NSEL,R,LOC,Z,Zctipn

CM,CRACK_FRONT_NODE_CMn

CINT,NEW,1

CINT,CENC,CRACK_FRONT_NODE_CM1,,11,2

CINT,CENC,CRACK_FRONT_NODE_CM2,,11,2

CINT,CENC,CRACK_FRONT_NODE_CM2,,n,2

Example 11.5: Defining the Crack-Extension Node Component and Crack-Extension Direction

! Crack-extension node component and

! crack-extension direction specification using vectors

NSEL,S,LOC,X,Xctip1

NSEL,R,LOC,Y,Yctip1

NSEL,R,LOC,Z,Zctip1

CM,CRACK_FRONT_NODE_CM1

NSEL,S,LOC,X,Xctip2

NSEL,R,LOC,Y,Yctip2

NSEL,R,LOC,Z,Zctip2

CM,CRACK_FRONT_NODE_CM2

NSEL,S,LOC,X,Xctipn

NSEL,R,LOC,Y,Yctipn

NSEL,R,LOC,Z,Zctipn

CM,CRACK_FRONT_NODE_CMn

CINT,NEW,1

CINT,CENC,CRACK_FRONT_NODE_CM1, , , ,Vx1,Vy1,Vz1

CINT,CENC,CRACK_FRONT_NODE_CM2, , , ,Vx2,Vy2,Vz2

CINT,CENC,CRACK_FRONT_NODE_CM2, , , ,Vxn,Vyn,Vzn

11.3.5.2.3. Step 3: Specify the Number of Contours to Calculate

Specify the number of contours for the material force evaluation:

CINT,NCON,n

where n is the number of contours.

For 3-D crack geometry, every node along the crack front has the same number of contours.

Example 11.6: Specifying the Number of Contours to Calculate

CINT,NEW,1

CINT,CTNC,CRACK_FRONT_NODE_SET,NODE

CINT,NCON,6

11.3.5.2.4. Step 4: Define a Crack Symmetry Condition

If the crack is located along a symmetry plane and only a half model is created, define a symmetric
condition so that the program can account for it:

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Numerical Evaluation of Fracture Mechanics Parameters