Fatigue life refers to the number of cycles of loading a material can withstand before it fails due to fatigue. In engineering, fatigue failure occurs when a material is subjected to cyclic loading, such as repeated bending or twisting, and eventually fractures even when the applied loads are below the material’s ultimate strength. The fatigue life of a material is influenced by factors such as its composition, microstructure, surface condition, loading frequency, and stress range. Fatigue life is an important consideration in designing durable and safe products in fields such as aerospace, automotive, and civil engineering.

Thermal fatigue is a type of fatigue failure that occurs due to cyclic heating and cooling of a material, which causes it to expand and contract. This repeated thermal expansion and contraction can result in the formation of cracks and fractures in the material, eventually leading to failure. Thermal fatigue can occur in any material, but it is particularly problematic in metals, ceramics, and composite materials that are exposed to rapid and drastic temperature changes. Common examples of thermal fatigue include the failure of engine components in automobiles, turbine blades in power plants, and heat exchangers in refrigeration systems. Thermal fatigue can be mitigated by selecting materials with high thermal stability, designing components to minimize temperature gradients, and using appropriate thermal insulation and cooling systems.