Testing the fatigue life of metals under load control is the best way to obtain the fatigue strength in the fatigue regime where strains are predominantly elastic throughout the test. High-cycle fatigue (HCF) tests are often conducted on smooth bar specimens in load, force or stress control. The goal of the test is to determine the number of cycles to fracture for each specimen. Nominal stress levels in high cycle fatigue tests are relatively low and significantly below the metals yield strength. The final results are plotted as stress-life (S-N) curves. Applications that deform in predicable strain amounts should be tested with a strain control system. Also, strain control fatigue testing is necessary in applications which the mechanical properties of the material in question are strain rate sensitive. Strain control fatigue testing is often done to simulate the expansion and contraction of a material as temperatures vary. As a component is exposed to different temperatures is expands or contracts. When confined, components can be put under large stresses that eventually lead to fatigue failure.
ASTM E466 covers the standard practices for conducting force controlled constant amplitude axial fatigue tests of metallic materials. The test is used to determine the fatigue strength of metallic materials. TestResources sells axial fatigue testing machines that meet the requirements of ASTM E466. Our metal fatigue testers can be either servo hydraulic like the 910 Series fatigue test machine, or electrodynamic like the 800 Series fatigue test machine. Both of these metal axial fatigue testing machines meet the requirements of ASTM E466. Metal fatigue test machines can be controlled with high precision using one of TestResources controllers. Constant amplitude loading is a basic function of all of the controllers offered by TestResources. TestResources also sells fixtures for griping metal specimen during the fatigue testing.
Applicable Testing Standards
Recommended Test Machine
Static and fatigue forces up to 50 kN (11,250 lbf)
Frequency ratings up to 75 Hz
Oil-free, all electric actuator for clean test conditions
Lower purchase, operating, and maintenance costs than hydraulic equivalents
>Load ratings from 100 kN to 5 MN (22,500 lbf to 1,125,000 lbf)
Servohydraulic
Can perform both static and dynamic tests
Static and fatigue forces up to 25 kN (5,500 lbf)
Frequency ratings up to 100 Hz
Servohydraulic
Small, portable footprint
Recommended Testing Accessories
Load ratings from 50 kN to 300 kN (11,250 lbf to 67,500 lbf)
Hydraulic actuation
Designed to cycle dynamically through zero-load
Temperature ratings up to 1,000°C (1,800°F)
Measures displacement for axial tensile, compression, and cyclic testing
Gage lengths from 10 mm to 50 mm (0.5 in to 2.0 in)
Measuring ranges from 5% to 100% strain
Lightweight and self-supporting