Fatigue crack propagation study and life calculation in shafts stiffed by rotation bending

Fatigue fracture toughness of materials is one of the most important factors in calculating the fracture resistance of machine elements or parts under variable loads. This study in which fatigue fracture toughness value and fatigue crack propagation parameters of 36 Mn 5 used as Shaft Material were determined, consisted of two parts. In the first part of the thesis, theoretical information about the subject is given. It has been shown how to find the fracture toughness value with the standard method and the rotational flexure test. It also includes the fatigue crack propagation laws and the damage tolerance approach. In the second part, experimental studies have been done. Fracture toughness, fatigue fracture toughness, fatigue crack propagation rate and parameters of 36 Mn 5 material were determined. In this study, the tests and analytical solutions required for determination of fatigue fracture toughness with small rotating bending specimens were examined. A fast and inexpensive test method has been available for determining the fatigue fracture toughness (Kfc). It has been determined that the period bending fatigue test can be used to calculate the fatigue fracture toughness.