Vermoeidheidscracks

Vermoeidheidscracks, also known as fatigue cracks, are a type of fracture that occurs in materials due to repeated cyclic loading. This process is also referred to as fatigue failure. Unlike brittle fracture, which happens suddenly under a single overload, fatigue cracks initiate and grow incrementally over time with each load cycle.

The initiation of a fatigue crack typically begins at a stress concentration point, such as a small surface defect, a sharp corner, or a microscopic inclusion within the material. Under cyclic stress, these microscopic imperfections can lead to localized plastic deformation. With continued cycling, these small deformations can coalesce to form a microscopic crack.

As the cyclic loading continues, the crack grows. Each load cycle causes the crack to advance a small amount. This growth can be visualized as a series of striations on the fracture surface, with each striation representing the crack’s position after one load cycle. The rate of crack growth is influenced by factors such as the magnitude of the applied stress, the material properties, and the environment.

Eventually, the crack grows to a critical size. At this point, the remaining cross-section of the material is no longer strong enough to support the applied load. The component then fails suddenly, often in a manner resembling brittle fracture, though the underlying cause was fatigue. Understanding vermoeidheidscracks is crucial in engineering design to prevent premature failures in components subjected to repeated stresses, such as in aircraft, bridges, and rotating machinery.