Fatigue tests
Mechanical characterization of your material with fatigue testing
Check the dynamic mechanical performance at room temperature, cold or hot of your materials.
If your product is composed of materials subjected to time-varying stresses, you need this kind of testing. TEC Eurolab can identify material behavior by simulating actual operating conditions with fatigue tests.
Fatigue tests are fundamental destructive tests to evaluate the ability of a material to withstand repeated dynamic stresses over time. These tests make it possible to study the behavior of materials subjected to oscillating load cycles by simulating real operating conditions. Their importance is crucial for industries such as aerospace, automotive and biomedical, where component safety and reliability are essential. Through fatigue analyses, key information on material durability can be obtained by identifying the limits beyond which the material may fail, with the goal of preventing in-service failures.
The purpose of fatigue tests is to determine the behavior and durability of the material in a certain state of supply subjected to set fatigue cycles.
Based on the experimental results obtained, it is possible to reconstruct the Wöhler curves or Goodman-Smith diagram of the material itself, determining, where it exists, the fatigue limit or determining the effect of the material on the life of the component under defined loading conditions.
Material fatigue testing is performed when it is desired to characterize the behavior of a given material subjected to stresses below critical stresses, verifying its service life under a defined load profile, oscillating between a set maximum and minimum value.
Fatigue analysis of TEC Eurolab
At TEC Eurolab, we undertake materials fatigue testing to support companies in verifying the durability and reliability of their components under cyclic loading conditions. Using modern instruments such as vibrophores, servohydraulic machines, and electromechanical actuators, we can perform tests on a wide range of materials, from metals to composites to rigid polymers.
Our approach is based on the use of advanced technologies, qualified technical know-how, and long experience gained in various industries, such as aerospace, automotive, and biomedical.
At TEC Eurolab we can perform the following fatigue tests, from room temperature up to 1000°C:
- High Cycle Fatigue (HCF) axial fatigue test on single specimen
- Rotating Bending Fatigue (RBF) test on single specimen (room temperature only)
- Low cycle axial fatigue, Low Cycle Fatigue (LCF) test on single specimen
- Determination of the Wöhler Curve
- Determination of Fatigue Limit by staircase method
- Determination of coefficients for characterization of cyclic material behavior
Fracture mechanics
Supporting fatigue testing is fracture mechanics, which is able to determine how the effects of linear indications, such as cracks, and in general defects in a component, can change the mechanical behavior during failure of the material under study.
Being aware of fracture toughness values such as JIC, KIC and Fatigue Crack Growth Rate provides data that can be used to determine the suitability of a material to resist fatigue failure in real-world applications.
Having information regarding crack propagation rate and stress intensity factor is essential in Engineering Critical Assessment (ECA) studies and in selecting the appropriate material for components and structures where the minimum acceptable defect size has a decisive impact on the life of the component in service. Some of the fatigue tests we can perform at TEC Eurolab to verify fracture mechanics from room temperature up to 1000°C:
- Fracture toughness
- Fatigue Crack Growth Rate (FCGR)
- Determination of ΔK-threshold (ΔKth)
Residual stress
Residual stresses are internal stresses that remain in the material even in the absence of external loads. These phenomena can result from manufacturing processes, such as welding, machining or heat treatment, and significantly affect the behavior of the material during fatigue testing. Residual stresses can be verified regardless of whether a fatigue test is performed. But in the context of fatigue analysis, residual stresses play a crucial role, as they can reduce the life of the component or alter its performance. Measuring them and assessing their impact is critical to better understand the material’s response to repeated load cycles and to optimize component design and manufacturing. At TEC Eurolab, we test for residual stresses:
- On samples and components
- Superficial
- Sub-surface by electropolishing on artifacts or specimens
Dynamic analysis
In the field of fatigue testing, dynamic mechanical analysis aims to study the behavior of materials subjected to time-varying stresses. These analyses make it possible to simulate cyclic loading conditions typical of real applications, such as vibration, impact or oscillation, and to evaluate the dynamic response of the material, according to specific industry standards. They are performed on standardized samples. Dynamic analyses can also be performed on non-standardized components or samples. Custom dynamic tests on non-standard components are taken care of by our Test Engineering department. Thanks to this type of analysis, it is possible to verify the ability to withstand mechanical loads during the development of a new product or component, obtaining fundamental information on its future durability and reliability, identifying any structural criticalities or performance limits. These tests are an essential tool for ensuring the safety and efficiency of products in the most demanding environments.
Check the behavior of your material subjected to repeated fatigue cycles
Technical characteristics of the fatigue test
The fatigue tests performed by TEC Eurolab are designed to meet the specific needs of materials and components belonging to different industries. Using advanced instrumentation and established methodologies, we can perform fatigue analyses that simulate real operating conditions and guarantee reliable and repeatable results.
Each fatigue test is designed on the customer’s specific request and material characteristics, including tests at room temperature, hot or cold, to evaluate the strength of the component under cyclic loads. The data collected are critical in determining the service life of the component and identifying fatigue behavior.
The methodology
Fatigue tests performed by TEC Eurolab follow a rigorous methodology structured to ensure accurate and reliable results. Each test begins with the definition of cyclic loading parameters, which include the maximum and minimum voltage range, frequency and number of cycles, in order to simulate the real operating conditions of the component.
During a fatigue test, materials are subjected to controlled load cycles, and through data acquisition and analysis, curves such as Wöhler curves or Goodman-Smith diagrams are constructed, which are useful in determining the fatigue limit or the effect of dynamic loading on component life.
This approach allows each fatigue test to be tailored to the customer’s specific needs, ensuring that the results obtained are directly applicable to the industrial context.
The instruments of the fatigue test
The equipment pool that TEC Eurolab provides for performing fatigue tests on materials consists of several machines.
Vibrophores
These are fatigue testing machines that take advantage of resonance to perform tests at high frequencies (100-130Hz), in short times and at high loads. Tests can also be performed at high temperature up to 1000°C.
Vibrophores are used for performing Push-pull HCF (High Cycle Fatigue) fatigue tests to determine the fatigue strength properties of metallic and composite materials.
Depending on the state of material supply, specimens of cylindrical or flat geometry can be obtained.
It is also possible to employ vibrophores to perform fatigue tests on fasteners for the purpose of validating entire production batches.
Rotating bending machine
The Rotating Bending Fatigue machine enables alternating stress fatigue testing on cylindrical specimens (Rotating Bending Fatigue RBF ).
Unlike the other systems, the machine rotates the specimen along its axis by applying a certain bending moment to it.
Electromechanical machines
TEC Eurolab has 5kN and 15kN electromechanical recirculating ball actuators. These systems are mainly used to perform fatigue tests on polymeric and composite materials.
The machines are equipped with a climatic chamber that allows tests to be performed from a temperature of -40° up to 180°C.
Dedicated equipment can be made to perform customized tests according to customer specifications.
Servohydraulic machines
TEC Eurolab provides the customer with servohydraulic testing machines with a 100kN bottom scale, with the possibility to perform the dynamic tests even at high temperatures, up to 1000°C, through the use of a furnace. In addition to HCF tests, these machines equipped with special extensometers allow for oligocyclic LCF (Low Cycle Fatigue) and fracture mechanics tests.
The industries we target
Materials fatigue testing finds application in numerous industries where component safety, reliability and durability are critical. Prominent among the industries involved are aerospace, automotive, biomedical, oil & gas, and rail, which require rigorous fatigue testing to ensure optimal performance even under extreme operating conditions.
Through fatigue testing, the behavior of critical materials and components for aircraft structures, high-performance vehicles, medical devices or power plants, and any type of metallic, composite, and carbon fiber materials can be evaluated, helping to improve design and reduce the risk of failure in service. These analyses are essential to ensure compliance with quality and safety standards required in highly regulated environments.
Our fatigue testing videos
Do you need to perform a fatigue test?
Fatigue strength analysis of Alsi10Mg aluminum alloy using Additive Manufacturing technology
The majority of causes of component failure in service are related to fatigue phenomena.
The present study was carried out on components made of aluminum alloy AlSi10Mg fabricated by powder bed additive technology. Additive technology allows significant structural and thermo-fluid-dynamic advantages related to the shape of the components: it provides much higher densities than castings, however, it is not capable of realizing a material density comparable to material obtained from solid (rolled or drawn).
White Paper | LCF (low cycle fatigue) and HCF (high cycle fatigue) fatigue test on metallic materials
FAQ - Fatigue Testing
Among the types of mechanical tests, what are torque tests used for?
Torque tests are used to verify the torsional behavior of threaded components. These can be used to define defined parameters for the use of threaded couplings, such as screwing and unscrewing torques.