What are vibration tests?
Vibration tests simulate mechanical loads that act on a test specimen through shocks or shaking movements. Unlike a hammer blow, these are continuous vibrations. The aim is to test the loads to which a test specimen could be exposed in real use. A typical example is components that are installed in a truck.
When is a vibration test required?
A vibration test is required when components are exposed to vibrations during operation or transportation. Vibrations occur whenever something moves. This mainly affects components in vehicles such as cars, commercial vehicles or machines. These loads can lead to wear, material fatigue or damage.
Types of vibration tests
- Random vibration (random excitation)
- In this type of test, a so-called noise profile acts on the test specimen. The excitation is random and unpredictable, as it depends on factors such as road conditions, vehicle speed or vibrations during transportation. This type of test is particularly relevant for components that are installed in vehicles or transport containers.
- Typical loads:
- High acceleration peaks
- Unpredictable vibration patterns
- Sinusoidal vibration (sinusoidal excitation)
- In this test, a uniform, sinusoidal excitation acts on the test specimen. This type of excitation occurs when components are installed in the vicinity of rotating machines such as motors or gearboxes.
- Example:
- A motor running at 3000 revolutions per minute generates an excitation of approx. 200 Hertz. If a circuit board has a natural frequency of 200 Hertz, resonance can occur, causing components to vibrate strongly and, in the worst case, break off or come loose.
- Typical loads:
- Uniform vibrations
- Higher stress with resonance
Why are natural frequencies important?
The natural frequency describes the frequency at which a component naturally vibrates. If the excitation frequency of a sinusoidal vibration matches the natural frequency, resonance occurs. This resonance greatly amplifies the vibrations and increases the stress on the component, which can lead to defects.
What can be done about this?
- Adapt the design of the components so that the natural frequency is significantly higher or lower than the excitation frequency.
- Design components in such a way that they can better dampen or dissipate mechanical vibrations.
When is which test used?
- Random vibration is always used when the test specimen is subjected to stress during transportation, travel or general mechanical movement. Examples: Electronics in vehicles, transport containers, freight.
- Sinusoidal vibration is used when components are installed in the vicinity of rotating machines such as motors, gearboxes or wind turbines.
Conclusion
A vibration test is always useful when components are exposed to mechanical loads due to movement, transportation or operation. The choice of test (random or sinusoidal) depends on the type of load. The simulation of these loads helps to ensure the longevity and reliability of components.
Do you have any questions?
If you would like to know which type of vibration test makes the most sense for your product, please contact us. Our team will help you choose the right test and ensure that your product is tested optimally.
