Fatigue is a type of failure that occurs in materials when they are subjected to repeated or cyclic loading. It is a common type of failure in engineering structures and components, such as bridges, aircraft, and machinery, that are subjected to repeated loads over their lifetime.
When a material is subjected to a load, it will undergo some level of deformation, which is called strain. When the load is removed, the material will return to its original shape, which is called recovery. If a material is subjected to a load that is below its yield strength (the point at which it begins to deform permanently), it will recover completely when the load is removed. However, if the material is subjected to a load that is above its yield strength, it will undergo some level of permanent deformation, which is called plastic deformation.
When a material is subjected to repeated or cyclic loading, it will undergo alternating periods of strain and recovery. If the cyclic load is high enough, the material may undergo plastic deformation with each cycle, which can lead to the accumulation of strain over time. As the strain accumulates, it can cause the material to become weaker and more susceptible to failure. This process is called fatigue.
The fatigue limit of a material is the maximum stress that it can withstand under cyclic loading without failing due to fatigue. The fatigue limit is usually lower than the ultimate tensile strength of the material, which is the maximum stress that it can withstand before breaking under a single, static load.
In engineering design, it is important to consider the fatigue properties of materials and to design structures and components to avoid fatigue failure. This may involve selecting materials with high fatigue limits, designing structures to distribute loads evenly, or using fatigue-resistant design techniques.
Tags: Concept of Fatigue in Materials
