Hello

I hope you are doing well. My query is what is the relationship between energy release rate (G) and Stress intensity factor (K) in 3D? The relationship is as shown below https://en.wikipedia.org/wiki/Energy_release_rate_(fracture_mechanics).

G=k1^2/E for plane stress

and

G=(k1^2)*(1-nu^2)/E for plane strain

where E and nu are modulus of elasticity and Poisson ratio

But all these relations are only for plane stress or plane strain. What is the relationship for 3D problems? I am very confused. Please help.

Regards

Bhanu