Fatigue in materials

Fatigue in materials is the progressive change of structure and mechanical properties produced by frequent loading and unloading of the material. Such repetition of stress cycles leads to progressive deterioration of the cohesion of the material, particularly in the case of metals. This deterioration is the cause of a high proportion of failure in structures and machine parts. Such failures can cause loss of life, as in the case of aircraft accidents or the collapse of bridges.
It is estimated that material fatigue accounts for 90% of the failure of parts or structures in service.
(D) Detailed problems