Common fatigue tests
Materials and components may fail prematurely under oscillating loads. For this reason, the behavior of materials under alternating mechanical loading is an important decision criterion, for which the necessary data are obtained through testing.
There are two categories of fatigue in materials testing:
Crack growth curve
The crack growth of a material is described in the crack growth curve.This curve is divided into three regions:
- Region I: low crack growth rate; initial dKth value at which crack growth is just beginning
- Region II: constant crack growth rate; is mathematically described with the Paris straight line
- Region III: high crack growth rate; ends with fracture K1C
