In reality, many mechanical components are not destroyed by a single large load, but by repeated loads over a long period . This is the cause of material fatigue. Therefore, fatigue testing plays a crucial role in evaluating the strength, lifespan, and reliability of a product before it is put into use.
In the automotive and aerospace industries , components and structures are constantly subjected to varying loads throughout their operation. Vehicle chassis experience vibrations from the road surface, suspension systems are constantly subjected to tension and compression, while aircraft wings and other aerospace structures are subjected to repeated aerodynamic loads over thousands of operating cycles. Therefore, fatigue testing is a crucial step in evaluating the durability and lifespan of a product before it is put into practical use.
What is fatigue testing?
Fatigue testing is a method for checking the ability of a material or product to withstand cyclic loading. During the test, the sample is subjected to tensile, compressive, bending, torsional, or a combination of forces for a defined number of cycles.
A key characteristic of fatigue is that materials can crack and fail even at loads significantly lower than their static strength limit. Therefore, performing only conventional tensile or compression tests is insufficient to assess the lifespan of components subjected to frequently varying loads.
Principles of fatigue testing
The fatigue testing machine applies a cyclically varying load with controlled force, amplitude, and frequency. The system continuously records force, displacement, strain, and cycle count until the specimen reaches the test condition or failure occurs.
Depending on the application, fatigue testing machines can utilize electromechanical, electric servo, or hydraulic servo mechanisms to meet varying load and frequency requirements.
Common methods for assessing fatigue strength
Some commonly used testing methods include:
- - Tensile and compression fatigue test: Applying repeated tensile and compressive forces to the sample.
- - Flexural fatigue test: Evaluates the ability of a material to withstand periodic bending stress.
- - Torsional fatigue test: Suitable for shafts, connecting rods, and other components subjected to torque.
- - Multi-axis fatigue testing: Combines various load types to more accurately simulate real-world working conditions.
- - SN curve: Defines the relationship between stress level and the number of cycles a material can withstand before failure.
The role of fatigue testing in automotive and aerospace testing.
Fatigue testing is widely used in automotive, aerospace, railway, mechanical engineering, construction, and materials research . Test results help engineers select materials, optimize designs, predict lifespan, and identify potential weaknesses in products.
In the automotive industry , fatigue testing is applied to vehicle frames, chassis, suspension systems, control arms, springs, axles, wheels, seats, and many other structural components. In particular, hydraulic servo testing systems can replicate road loads to assess the durability of components or entire vehicle assemblies.
In the aviation industry , fatigue testing plays a crucial role for aircraft wings, fuselages, landing gear, connecting structures, and components subjected to aerodynamic loads. Simulating thousands of takeoff, flight, and landing cycles helps assess structural lifespan and detect early signs of potential crack development.
With the ability to simulate real-world loads and conduct tests under controlled conditions , fatigue testing systems are crucial tools for automotive and aerospace manufacturers to optimize design, verify durability, predict lifespan, and improve product safety.
Contact GPower Vietnam for detailed advice on the most suitable fatigue testing system for your business.
Info@gpower.com.vn
