Learning Forum

[ferdinand.doemling]

Hi all,

2.4. Fracture-Parameter Calculation Types
provides us with an explanation for the CINT command and the use of the interaction integral implemented in ANSYS.
Can someone please explain to me whether the following description is contradictory or whether it is a misunderstanding on my part. Is the SIF at the end nodes now calculated via plane-stress or plane-strain? 

Thanks in advance

Ferdinand

Quote:

2.4.2.3. Selecting Auxiliary Crack-Tip Stress Fields

[...]

For 3D crack models, Mechanical APDL determines whether a crack is closed or open. In a closed crack, the end-points of the crack front are the same (for example, a penny-shaped crack). In an open crack, the end-points of the crack front are distinct (for example, an edge crack in a compact-tension specimen).

For closed cracks, plane-strain auxiliary fields are used in the SIFS calculations.

For an open crack front, plane-stress auxiliary fields are used at the end nodes of the crack front, while plane-strain auxiliary fields are used at the interior nodes during the SIFS calculations.

For an open crack, you can control the behavior of auxiliary fields via Par2 on the CINT command (CINT,TYPE,SIFS,Par2 command):

• • Default: Plane-strain auxiliary fields on the interior nodes of the crack front (CINT,TYPE,SIFS or CINT,TYPE,SIFS,0). The stress-intensity factors at the end nodes are set to copy the stress-intensity factors at the adjacent nodes.

  • Plane-stress auxiliary fields over the entire open crack front (CINT,TYPE,SIFS,1).

  • Plane-strain auxiliary fields over the entire open crack front (CINT,TYPE,SIFS,2).
    

 

[danielshaw]

The behavior of the auxiliary stress fields is explained in the documentation for the CINT ommand.  I believe that the other section of the documenation first explains the default and then explains the user options.

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