Example 2:
! Select nodes located along the crack front and
! define it as crack front/tip node component
LSEL,,,,
NSLL
CM,CRACK_FRONT_NODE_CM,NODE
CINT,NEW,1
CINT,TYPE,VCCT
CINT,CTNC,CRACK_FRONT_NODE_CM11.3.2.2.2.2. Specifying Crack Information When the Crack Plane Is Not Flat
This approach applies to 3-D curved crack planes, where a unique normal may not exist. However, you
must define the crack-extension node component and the crack-extension direction at each crack-tip
node location:
- Define a node component consisting of one or more nodes forming the crack tip.
The node component can have one or more nodes.Example:CINT,CENC,CompName- If the node component has more than one node, identify the crack-tip node separately.
If a crack-tip node is not identified, the first node of the node component is used as the first node.Example:CINT,CENC,CompName,Node1- Define the crack-extension direction.
Identify the local coordinate system associated with the crack under consideration, and identify the
local axis along which the crack should extend.Example:CINT,CENC,CompName,Node1,11,2Alternatively, define the crack-extension direction by directly specifying the global X,Y, and Z
components of the crack-extension vector.Example:CINT,CENC,CompName,Node1,,,compx,compy,compzRepeat this method for all node locations along the crack front. Although the program automatically
calculates the local coordinate system at the crack tip to determine the energy-release rate, it is usually
best to use the NORM option to help align the calculated normals of the crack-tip nodes.
Example 1:
! Local coordinate systems
local,11,0,,,,
local,12,0,,,,
...
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
...Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential informationNumerical Evaluation of Fracture Mechanics Parameters