Mechanical stress or fatigue often lead to cracking or a component failure by fracture. Crack distribution, fracture surfaces and material properties as well as the microstructure structure formation allow to draw conclusions about the cause of the damage.

In many cases, clear statements about the present damage mechanism as well as conclusions about the damage process be drawn by expert evaluation of these characteristics and features.

Engineer standards: VDI- Norm 3822 Page 2,3