Vibration Research’s random PSD averaging method provides the smoothest control lines in the industry. The iDOF® software allows engineers to run highly accurate vibration tests in a condensed period, ensuring that their product is tested for just the right amount of time. iDOF is a Random software add-on (VR9210).
Testing facilities in industries such as aerospace often test high-value equipment at extremely high levels of random vibration for a brief period. The goal is to run a realistic test that will identify reliability issues without damaging the equipment.
Ideally, engineers want to see a smooth control trace on the power spectral density (PSD) that stays within an established tolerance range. However, short-duration random vibration tests typically have very tight tolerances (±1.5dB). The statistics of averaging FFT power values limit the possibility that all lines will be within tolerance in a short timeframe.
The iDOF software calculations are a statistically valid way to provide smooth lines and an in-tolerance PSD in a brief testing period.
Time constraints and the statistical nature of the PSD calculation make it difficult to create a smooth PSD that accurately reflects the test results in a short duration. Popular methods that address this challenge hide the true test response of a device under test (DUT).
The iDOF software takes a statistically valid approach to quickly creating an accurate PSD. At each change in the test level, iDOF reduces the variance of the PSD estimate and exposes any lines out of tolerance without masking resonances.
With iDOF, engineers can verify that the control PSD is within tolerance and determine how the test affects the DUT. Most importantly, they can stop the test before the energy from a resonance inflicts damage on the DUT.
When Should I Use the iDOF software?
You are performing short-duration vibration tests and want to avoid over/under-testing
You have a high-value product or a complex test setup likely to change response as test levels increase
You have system noise and want to change levels quickly
Aerospace Vibration Testing
Aerospace vibration testing requires adequate test severities and consistent, repeatable results. Vibration Research offers many aerospace testing solutions, including short-duration random tests with the iDOF software, high-channel-count control, shock response spectrum (SRS), and more.
Engineers and lab managers appreciate the “perfect world scenario” that iDOF offers. It is an innovation the vibration control industry has needed for some time.
With iDOF, Your PSD Plots Will
Display incoming test data throughout the test
Abide by the user-defined degrees-of-freedom (DOF)
Reset averaging during test level changes
Engineers can expect a quick, smooth line except when real-life resonances and vibration patterns dictate that a raggedness should appear. They can abort the test before any potential product damage occurs.
Too often, software force-fits a smooth line by running the test at a low level (i.e., below demand) and multiplying the average PSD by a factor to bring it to full level. This method is invalid because it falsely assumes that the behaviors of the DUT at a high level mimic that of a low level. This averaging method is unfortunately common, and it is why high-value products are over/under-tested.
Harness the exactness, efficiency, and peace of mind that the iDOF software offers to vibration control engineers.
iDOF Software Webinar
Faster than Traditional Averaging
Control errors are visible much sooner with iDOF than with traditional averaging. For example, the iDOF algorithm can process ten frames of data to produce a PSD estimate comparable to traditional averaging with 100 frames. This processing time enables fast detection of changing responses such as shifting resonances without using long averaging times: a critical capability for short-duration tests.
Random Vibration Testing in VibrationVIEW
With 104,000 lines of control (26,000 with the VR9500), the VibrationVIEW Random software provides the highest possible control in an easy-to-use interface. Analyze random data with a comprehensive suite of graph display options or generate a test from recorded data with our advanced test development options.