The prediction of crack growth is at the heart of the damage tolerance discipline.

Therefore a more general theory of crack growth is needed for elastic-plastic materials that can account for:

As the tire became thinner due to wear, the dynamic forces were exaggerated, resulting in crack growth.

Then it is less likely that any one spot will experience thermal shock above the threshold required to initiate crack growth.

Consequently, they become prone to premature fracture because of sub-critical crack growth.

The rubber product must be under tension for crack growth to occur.

The crack growth becomes unstable and accelerates resulting in a fracture of the specimen.

Wohler showed clearly that fatigue occurs by crack growth from surface defects until the product can no longer support the applied load.

Rice also showed that the value of the J-integral represents the energy release rate for planar crack growth.

The earliest fracture mechanics approach for unstable crack growth is Griffiths' theory.