Determine stress concerntration factor via J-intergral

[yaz05]

Hi everyone,

I am trying to determine stress concerntration factor near a sharp corner in a linear elastic Ansys model. I have created a path (see attachment)and I want to calculate SCF via 3D J intergral.
My question is, can I use CINT command to find SCF for a sharp corner? Has anyone any other sugguestion I can find the SCF for the sharp corner using Ansys workbench?

Best Regards
Yaz

 

[rb1957]

i thought J intergal gave you stress intensity. i guess in the absense of a crack this'd be stress concentration.

why not use the FE output directly ... nodal stress on the surface of the notch ?

are you running inelastic FEA ?

why not use ncode (or something similar) to do the fatigue analysis within the FEA ?

 

[ZeroExperience]

How much does nCode cost?

 

[Andries]

Hi yaz05,

The J-integral is used to establish the strain energy release rate in elasto-plastic fracture mechanics. For linear elastic fracture it will give the fracture toughness of the material.
You are probably thinking of the stress concentration factor, which is a different parameter. It can be calculated numerically but a very fine mesh would be required in the vicinity of the stress raiser. In your example, where thin-walled members are joined, you would probably have to mesh a typical feature through the thickness with a large number of elements. It could become a huge analysis so maybe you should try some other strategy around the problem. Is the structure subject to fatigue loads? If not, and the material is ductile, you could allow for local plastic deformation to reduce the stress levels in the high-stress region.

Andries

 

[bxtsafe]

yaz05, I didn't understand what is the problem.

I agree with Andries: if fatigue is not important, probably it is possible to accept an little amount of yielding in order to validate this problem.