The purpose of vibration testing is to determine the ability of an object to retain its properties and integrity under the vibration of a given degree of rigidity. Vibration shakers are designed to test the product for vibration strength and resistance as per the highest requirements.
Hydraulic shakers are used:
- at considerable loads;
- for reproducing significant movements
- at low and medium frequencies.
Electro dynamic shakers are used:
- frequency range 10 Hz – 3.5 kHz
- short displacements
- good vibration acceleration and push force performance
- low transverse vibrations
- Sine on Random
- Classical Shock
- Replication Waveform
Pre-test and resonance search modes are used for system setup and test preparation.
Before conducting the vibration tests it is necessary to make sure that the sensors and the shaker are connected correctly, the tested object is installed and fixed and the test parameters are set.
To control the level of input vibrations on the tested object, the test engineers use feedback sensors. However, the sensor can only control the vibration level, but is not able to change the resonance behaviour of the system.
In order to improve the quality of tests and control the influence of resonance and antiresonance phenomena on their course, the control system has a pretest mode.
The controller gives a signal at different frequencies and determines the presence of resonances, after their detection it adjusts the transfer coefficients. The result is an inverse model, which is then used in testing.
Resonance search, tracking and holding at resonance is used for fatigue and durability testing at resonance frequency, determination of dynamic properties of the test object.