A vibration environment is not always purely random or sinusoidal, but rather a combination of vibration modes. Mixed-mode vibration testing is used to simulate these complex field environments. VibrationVIEW includes three methods of mixed-mode testing: Sine-on-Random, Random-on-Random, and Sine-on-Sine.
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Run mixed-mode tests with sine tones superimposed on a random background.
SoR is a mixed-mode test with sinusoidal vibration superimposed on a random background. The sine and random vibrations are performed simultaneously to simulate a service environment where both modes are present.
In an SoR test, the background vibration is generated in a random form. However, any sinusoidal vibration present that exceeds the g levels of the random profile must be included in the test profile to provide the most accurate representation of the in-service environment.
Up to 32 Sine Tones
One to 32 floating-point precision sine tones can be superimposed on the background random spectrum and swept back-and-forth between frequencies at a user-programmable rate.
Generate an accelerated Sine-on-Random test reflective of an environment with dominant sinusoidal vibration.
STAG is a real-world evaluation for products that experience dominant rotational vibration rendered as sinusoidal on a shaker table.
Standard random vibration test acceleration cannot accurately replicate an environment with dominant rotational vibration because both the sine and random background vibration must be analyzed and generated. The more accurate option is a combination of sine and random testing. A Sine-on-Random test can replicate dominant sinusoidal vibration and its orders as well as produce more consistent results than a random test.
The STAG software allows the user to analyze the order content of a waveform. The orders are then extracted, and accelerated sine tone profiles are generated. The accelerated profiles are combined with the FDS analysis of the remaining random content. Combined with FDS, the STAG tool allows for the analysis, acceleration, and generation of a real-life test.
Requires ObserVIEW and VibrationVIEW software.
STAG Software
Superimpose controlled bands of random energy on a random background.
A Random-on-Random (RoR) test runs a complex test profile that contains two types of random signals: random background and narrow-band signals. This mixed-mode test reflects field environments where the device under test generates a broadband random signal and one or more random “tones.” The narrow-band signals can be swept or fixed frequency and are superimposed on the base random energy profile. The random vibrations are performed simultaneously to simulate a service environment where both modes are present.
Up to 32 Narrow Spectral Bands
Define up to 32 narrow spectral bands to superimpose on the background random spectrum and sweep between frequencies at a user-programmable rate. The software allows for individuals sweep rates for each random “tone.”
Run a multi-sine test with up to 32 sine tones simultaneously.
Engineers often use a standard SRTD test to bring the device under test (DUT) to failure. For fatigue testing, the engineer may need to run multiple sweeps through the frequency range at different sweep rates. The time required to do so can exceed tens of hours.
With a multi-sine vibration test, the engineer can run multiple sine tones at different rates simultaneously. This feature saves time for engineers running fatigue testing and allows for the excitation of multiple resonant frequencies at once.
Up to 32 Sine Tones
One to 32 true floating-point precision sine tones can be superimposed on the background random spectrum and swept back-and-forth between frequencies at a user-programmable rate.
