Crack propagation modeling
Fracture mechanics

Crack propagation can be described in terms of three main stages:

• stage I: crack micropropagation around the K_s cracking threshold;

• stage II: Paris estate ;

• stage III: propagation accelerates as K_max approaches the critical FIC value, K_IC. Above K_IC, unstable fracture occurs.

Figure 10 describes these stages of propagation kinetics obtained during fatigue cracking tests on standardized specimens.

Crack propagation laws are based on the relationship between stress intensity factor and crack advance. The simplest is the Paris law given...