What is Fatigue Testing?
Fatigue testing is a type of mechanical testing used to evaluate a material’s ability to withstand repeated cyclic loading over time. It helps determine the fatigue strength, fatigue life, and endurance limit of a material, which are critical for predicting its long-term performance under fluctuating stress conditions.
Why is Fatigue Testing Important?
Prevents unexpected failures in engineering components.
Ensures safety in structures, automobiles, aircraft, and medical implants.
Helps in material selection for applications involving cyclic loading.
Aids in improving design by understanding crack initiation and propagation.
Types of Fatigue Testing
High-Cycle Fatigue (HCF) Testing
Used for materials experiencing low stress over a large number of cycles (typically >10⁵ cycles).
Conducted at relatively low stress levels.
Example: Aircraft wing structures, turbine blades.
Low-Cycle Fatigue (LCF) Testing
Used for materials experiencing high stress over a smaller number of cycles (<10⁵ cycles).
Plastic deformation occurs before failure.
Example: Engine components, pressure vessels.
Thermal Fatigue Testing
Evaluates material behavior under cyclic temperature variations.
Important for components exposed to thermal expansion and contraction.
Example: Exhaust manifolds, gas turbine parts.
Corrosion Fatigue Testing
Examines fatigue behavior in corrosive environments.
Helps understand combined effects of mechanical stress and chemical degradation.
Example: Offshore structures, pipelines.