What is high cycle and low cycle fatigue?

High cycle fatigue require more than 104 cycles to failure where stress is low and primarily elastic. Low cycle fatigue is characterized by repeated plastic deformation (i.e. in each cycle) and therefore, the number of cycles to failure is low.

What is meant by low cycle fatigue?

LCF is a type of fatigue caused by large plastic strains under a low number of load cycles before failure occurs. High stresses greater than the material yield strength are developed in LCF due to mechanical or thermal loading. The stresses may exceed the yield strength and cause large plastic deformation.

What is considered high cycle fatigue?

High cycle fatigue is a type of fatigue caused by small elastic strains under a high number of load cycles before failure occurs. The stress comes from a combination of mean and alternating stresses. HCF requires a high number of loading cycles to reach fatigue failure mainly due to elastic deformation.

Which is the dividing line between high cycle fatigue and low cycle fatigue?

Fatigue that occurs at relatively large numbers of cycles. The arbitrary, but commonly accepted, dividing line between high-cycle fatigue and low-cycle fatigue is considered to be about 10.000 to 100.000 cycles.

What are the characteristics of low cycle fatigue?

Low cycle fatigue has two fundamental characteristics: plastic deformation in each cycle; and low cycle phenomenon, in which the materials have finite endurance for this type of load.

Why is low cycle fatigue important?

The LCF result allows us to study the behavior of the material in greater depth to better understand the complex mechanical and metallurgical phenomena (crack propagation, work softening, strain concentration, work hardening, etc.).

What is high cycle fatigue testing?

High cycle fatigue testing is typically conducted on specimens in load/stress control to develop Stress-Life (S-N) Curves. An S-N Curve is generated by testing samples at a constant load/stress and recording the number of cycles to failure. The data is then compiled and a best trend fit is applied.

What is cumulative fatigue?

First let’s define what Cumulative Fatigue Training is. This is the act of performing a number of sets at a given weight for the same number of reps until you fail in your attempt to get the prescribed rep number. It is most commonly used in a paired sequence like 6×6 or 5×5 or 3×3.

What is high cycle fatigue failure?

HIGH CYCLE FATIGUE. Historically, high cycle fatigue (LCF) refers to situations that require more than 104 cycles to failure where stress is low and deformation is primarily elastic . In high-cycle fatigue situations, materials performance is commonly characterized by an S-N curve , also known as a Wöhler curve .

What is mechanical fatigue?

Mechanical Material Fatigue. Material fatigue is a phenomenon where structures fail when subjected to a cyclic load. This type of structural damage occurs even when the experienced stress range is far below the static material strength. Fatigue is the most common source behind failures of mechanical structures.

What is fatigue ratio?

fatigue ratio. noun. : the ratio of the fatigue limit or fatigue strength to the static tensile strength of a material. — called also endurance ratio.