Run mixed-mode tests with sine tones superimposed on a random background
Sinusoidal and random vibrations often exist simultaneously. With the Sine-on-Random software, you can generate sine and random vibration to simulate the service environment of a product where both modes are present. Sine-on-Random is one of the three mixed-mode testing modules in VibrationVIEW.
Sine-on-random is a mixed-mode vibration test that runs sine and random vibration. One or multiple sinusoids are superimposed on a random test profile, and the control system outputs the signals to the shaker table at the same time.
Easy Test Entry
The background vibration of an SoR test is random vibration. Any sinusoidal vibration that exceeds the acceleration of the random profile should be in the test profile for an accurate representation of the in-service environment.
In VibrationVIEW, engineers can define individual control channels, notch profiles, tuning parameters, and tracking filters for each sine tone and the random vibration. VibrationVIEW supports over 1,000+ breakpoints, suitable for virtually any test specification.
Enter the frequency or amplitude breakpoints of the background random acceleration spectrum in an easy-to-read tabular format. Alternatively, enter one endpoint and the desired dB/octave slope.
One to 32 floating-point precision sine tones can be superimposed on the random background spectrum and swept back and forth between frequencies at a user-programmable rate. The amplitude and frequency sweep parameters are also user-programmable.
Reference Output (Optional) VR9104
A second output channel to supply a synchronization signal of the first sine tone.
Random Import (Optional) VR9204
Import analog or digital time data to automatically generate a profile or import PSD data.
Sinusoidal and random vibrations often occur simultaneously, and a vibration test should always reflect the field environment. If a product primarily experiences random vibration, but there are sinusoids with considerable acceleration (g) levels, then the engineer should include the sine tones.
An SoR test is the best test method when sinusoidal vibration affects the underlying background random vibration. For example, all in-service aircraft, including fixed-wing, rotor, or rocket-propelled, have an inherent base random energy. A sinusoidal vibration is also present at various frequencies, typically from the turbine engine or rotor blade. As such, SoR is an ideal test method for many aerospace applications.
Watch: Sine-on-Random Test Startup
How to Establish the Correct Profile?
There are two approaches to consider when creating an SoR test profile. First, you can run the test according to the MIL-STD-810H specifications. This military standard is applicable and easy to use whether the device under test is for a military or civilian application, as many of the test articles are the same or similar.
The second approach is to record field data. Using analysis tools, you can determine the characteristics of the field environment required to create a realistic test profile. Modern vibration data recorders have simplified the process of collecting data from the field. To address the extensive analysis portion, Vibration Research developed Sine Tracking, Analysis and Generation (STAG).
Sine Tracking Analysis and Generation
Engineers can create an SoR test with recorded data using the Sine Tracking, Analysis and Generation (STAG) software. STAG generates SoR tests reflective of environments with dominant rotational tones that are rendered as sine tones on a shaker table. STAG is a real-world evaluation for products that may experience these dominant sinusoidal components, such as engine components.