Fracture theory

In this topic you will find information about fracture theory, useful in the KI Analysis.

Energy Release Rate

The energy release rate J or G can be related to the stress intensity factors by the following Irwin's relation :

with :

• : Energy release rate,

• : Stress intensity factors,

• : For plane stress (used in Icasoft), is equal to the Young modulus.

In Icasoft, J is calculated independently from

The stress intensity factors can by calculated using the interaction integral :

with :

• : Interaction integral,

• : For plane stress (used in Icasoft), is equal to the Young modulus.

• : Stress intensity factors,

• : Mode 1,2 stress intensity factor.

In Icasoft, is calculated separately. Consequently, (respectively, ) is calculated by choosing (respectively, )