Fatigue Testing of Metals, Composites, Polymers and Rubbers
What is Fatigue Testing?
In real world applications all materials and products are subjected to a wide variety of vibrating or oscillating forces. Fatigue testing consists of applying a cyclic load to a test specimen or the component to determine in-service performance during situations similar to real world working conditions.
There are three common forms of fatigue behaviour: high cycle fatigue (HCF), low cycle fatigue (LCF) and thermo mechanical fatigue (TMF). The principal distinction between HCF and LCF is that HCF is characterized by low amplitude high frequency elastic strains, while LCF is characterized by high amplitude low frequency plastic strains.
Fatigue Testing for Endurance Limit?
To construct an S-N curve, a fatigue testing specimens are subjected to over 10 million cycles (10.0E+06) in order to determine its endurance limit or fatigue strength resulting in tests lasting a few days and sometimes weeks. As a result, there is a tendency to apply the stress cycle at a higher frequency to shorten the test duration. For metallic materials, ASTM E466 recommends frequencies between 0.01 Hz to 100 Hz. Localized yielding can cause specimen heating and that provides an upper bound on maximum frequency that can be applied to fatigue testing of specimens and components. Polymers and plastics on the other hand are more susceptible to heating from hysteresis effects and have heat dissipation problems. This coupled with their lower melting points can result in lower fatigue strengths at high testing frequencies. Polymers and plastics are generally tested at a frequency of 5 Hz.
Fatigue Testing Capabilities:
Specifications: ASTM E8, E21, E399, E1290, E1820, E466, E606, E647, BS 7448, ISO 12135
- Fatigue crack propagation [da/dN vs ΔK Studies].
- Fracture mechanics [K1c, J1c, CTOD] Testing.
- 3 – point bend testing of materials.
- Room temperature and high temperature tests.
- Low/High cycle fatigue (LCF/HCF) Testing.
- Elastomer Crack Growth Testing
AdvanSES’s fatigue testing lab can perform high cycle, fatigue, low cycle fatigue, and specialized programs on a range of polymers, composites, ferrous and non-ferrous metals, parts and components. Fatigue testing can be carried out in stress & force control, strain control or displacement control. The deformation modes under which fatigue tests are generally carried out are tension – tension, compression – compression, tension – compression and compression – tension.
Work with a true partner who understands your applications, creates the right testing setup, and adds value at every step of your material and product development cycle. AdvanSES has experience with metal, non-metals, polymers and rubbers and is a leading supplier to OEMs and Tier 1 suppliers worldwide.