Creating Test Profiles

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Sine

Sine testing is the simplest form of vibration testing and serves as an excellent point of entry for this study.

Modules 1.1 – 1.3 serve as an introductory tool to create profiles, graphs, and reports using VibrationVIEW.

Module 1.1 covers a basic Sine test. In addition to configuring system limits and inputs, create a simple sine sweep from 20 to 2,000 hertz (Hz). In Demonstration mode, the resonant frequencies are programmed on Ch2, Ch3, and Ch4 with Ch1 as the control. The Ch2 resonance will be used to show the test capabilities of VibrationVIEW.

Module 1.2 introduces Sine Resonance Track and Dwell (SRTD) by expanding on the test created in Module 1.1. After the sweep, generate a resonance table to display the resonances found during the sine sweep. Then, select the resonant frequencies and VibrationVIEW will dwell at the frequencies for a set period of time.

Module 1.3 completes the study of sine testing by introducing advanced test configurations. Every aspect of the test profile can be changed using the advanced test configuration, and many of these changes are made in this module.

Much like Module 1.2, the goal of this test is to conduct a sweep then a resonance track and dwell over a certain frequency range. In this case, the amplitude and force vary over the range. While dwelling at resonance, VibrationVIEW will track any phase changes caused by the deterioration of the product and make adjustments as needed.

Random

A breakpoint table must be entered in order to create a random test profile. The breakpoint table is a list of frequencies and the correlating PSD. It determines the power distribution over a range of frequencies.

Modules 2.1 – 2.4 begin with an introduction to random vibration testing and quickly accelerate to advanced random testing, kurtosis control, and transition band frequency.

Module 2.1 is a basic introduction to random testing. Create the breakpoint table, set the graphs, run the test, create reports, and evaluate the data. While the test is running, examine the relationship between Ch2 and the control channel (Ch1). Any resonant frequency will clearly show on the probability density graph.

Module 2.2 runs an advanced random test. Create the breakpoint table and explore the various tabs of the advanced random test configuration. Take special note of the Gaussian curve on the probability density function graph.

Module 2.3 serves as a comparison between Kurtosion®, Vibration Research’s patented method of kurtosis control, and traditional Gaussian random tests. Start with no kurtosis and incrementally increase to a kurtosis of 7. Examine the effects of increasing the kurtosis while maintaining the same acceleration profile.

Module 2.4 introduces transition band frequency, which dictates how long the random vibration will dwell at the higher amplitude vibrations. As the transition band decreases, the kurtosis increases. Combining kurtosis with a low transition band can create an incredibly violent, high acceleration test. This module shows the effects of varying both the kurtosis and transition band.

Shock

Module 3.1 runs a basic Shock test. The output is a positive trapezoid and the test produces a distinct sound. This test is designed to explain the concepts required for a Shock test and the parameters required to run a Shock test.

Mixed Mode

Module 4.1 is an introduction to MIL-STD-810. Create a helicopter vibration exposure test to replicate the vibration experienced in the general areas of a helicopter.

Module 4.2 introduces a mixed-mode Random-on-Random test. The test begins as a typical random test, but as time progresses, three narrowband sweeping spectrums rise out of the random band and sweep up while increasing in amplitude. Explore the effects of the sweeping bands on the random band of energy and the resonances of Channels 2-4.

SRS

Module 5.1 synthesizes a frequency vs. acceleration breakpoint table to create an SRS tab. Note the wavelets that appear on the SRS graph when creating the test. Make adjustments to the synthesis type to see the effects of each on the same breakpoint table.

FDR

Module 6.1 uses a pre-recorded file (.vfw) and replicates the data using the field data replication tool. This is a simple module that reproduces the noise created when a driver stomps on the accelerator in a vehicle.