Contact person
Eva Larsson
Filosofie kandidat
Contact Eva
Fatigue testing of materials and components
Fatigue testing is carried out with a cyclic load, until breakage occurs. The purpose is to determine the fatigue life and strength of a material or component. We perform both standardized and specialized fatigue testing on materials and components, for both machinery and products for construction and infrastrucrure.
Purpose
Fatigue test results are an important basis for assessing life expectancy and strength of materials, components or structures under cyclic load, or to ensure that the necessary safety criteria are met.
The question may vary with application. In low cycle fatigue (LCF), high loads are of interest, around the yields stress limit of the material, while in high cycle fatigue (HCF) lower loads with a large number of cycles are looked at, up to the so-called fatigue limit. In this area, so-called SN curves can be plotted to examine the relationship between load amplitude and service life. The test can be carried out in different ways, e.g. load-controlled (controlled force) or elongation-displacement controlled (controlled elongation/displacement).
In our laboratory in Borås, we can perform tests on everything from small test bars to complete components with a size over 10 meters, and with loads up to 20 MN (2000 metric tons). To determine fatigue limits (high cycle numbers) of materials that are not frequency dependent, our resonance machines allow load frequencies around 100 Hz. We can also use variable amplitude (spectrum fatigue), or simulate custom load spectra specific to the application.
Specialized test setups with multi-axial loads can be built up on test floors with attachment points, where load are applied with hydraulic cylinders.
Test assignments are often complemented with various add-on services, such as:
- Testing at elevated temperatures,
- Prediction of life expectancy, load analysis, reliability and uncertainty assessment,
- Spectrum fatigue (variable-amplitude loads),
- Fracture mechanical analysis,
- Tensile test with advanced measuring techniques, such as acoustic emission (AE) and digital image correlation (DIC) methods,
- Development of material models for FEM analysis,
- Validation and verification (V&V) for quality assurance of simulation models.
Method
Fatigue testing is carried out in our accredited laboratory in Borås. We are accredited for methods SS-EN 112370, ASTM E466, ASTM E606, ECE R55, SS-EN ISO 14801, SS-ISO 1099.
Deliveries
Fatigue test results may be in the form of Wöhler diagrams (S-N curves) showing load amplitude against number of cycles, determination of a fatigue limit or verification of service life. When an applicable standard exists, results may be delivered accordingly.
