stress intensity

[arash2000]

Dear all

What is stress intensity formula for three dimensional stress in terms of three principal stress (S1,S2,S3)?


thanks

 

[metengr]

arash2000;
Your post is confusing. There are various formulas for determining stress intensity factor based on crack type and geometry. Any fracture mechanics handbook lists these formulas.

Regarding principal stresses, I would use the Von Mises equation and determine an equivalent stress to use in the desired formulas above.