Broad-band random vibration

a program from the scope of ZETLAB VIBRO software suite

Broad-band random vibration - main interface of the program

The program Broad-band random vibration is intended for testing the specimen with the use of broad-band random vibration with a particular intensity degree.

Modern signal processing algorithms of the Broad-band random vibration program allow to reveal minor defects of the specimen as well as to find the location of the defect based on the signal received from the transducers. The program is also used for detection of the useful signal against the interference environment. This feature can be useful for package and transportation testing, operational testing, evaluation of residual operation life and transition to the pre-fault mode (as the safety factor reaches the level of 75%).

Broad-band random vibration program is included into the scope of ZETLAB VIBRO software suite. The program can be started from the VCS control panel. Before starting the program, it is necessary to configure the following parameters of the vibration testing procedure:

In order to start the vibration testing procedure, it is necessary to select a testing profile consisting of at least two points with different frequency.

Broad-band random vibration program supports a wide range of combined tests, including:

  • Sine-on-Random
  • Random-on-Random
  • Sine-and-Random-on-Random.

In order to activate these functions, select the required combination of test impacts (“Sine” and “Noise”) in the window of vibration testing profile editor.

The program also has the feature of proportional increase of the general vibrational acceleration level in automated mode. To enable this option, the operator has to set the total acceleration level, and the program will automatically the required coefficients so that the total acceleration level would coincide with the level, which has been assigned by the operator.

Broad-band random vibration - vibration testing profile
Broad-band random vibration - editing the vibration testing profile parameters

Configuration of vibration testing parameters and graph plotting is conducted in the “Parameters” tab. The configuration options include:

  • general parameters of the test procedure: averaging duration, decline rate at the limits of the profile, amplitude characteristic’s dynamic range;
  • configuration of spectrum displaying: smoothing, median filter parameters; smooth adjustment to the test profile; correction of spectrum based on external interference;
  • recording parameters in the case if the testing procedure is suspended.

The operator can also set the vibration testing schedule using the “Time” tab. To do that, it is necessary to set the testing range, the duration of each testing step and the ratio of current integral level to the level set in the test profile.

Admissible testing limits, which are used for suspending the vibration testing process, are set in the “Suspension” tab.

Another feature of the updated software is the preview of the vibration testing results for the set profile based on the results obtained in the course of the pre-test start of the system. The corresponding graphical information is available in the “Channels” tab.

Note

The information displayed on the graph is intended for informational purposes only. It notifies the user of the estimated results, which are likely to be obtained in the course of vibration testing for a particular profile.

Depending on the values set for the testing profile parameters, the system calculates statistical parameters based on the current load applied to the vibration exciter. These values are displayed in the “Statistics” tab. This option allows to evaluate the capacity of the vibration testing system prior to the beginning of test performance, thus securing the structural integrity of the instruments used.

The resulting testing profile can be saved as a separate file to be loaded using the program “Vibration testing profile configuration“.

Tests performance

The bottom section of the Broad-band random vibration program interface displays events log, which is used for storage of various data accumulated in the course of program operation.

The beginning of vibration testing process is controlled with the “Start” key.

The program initiates the test process as the system reaches 95% of the required vibrational acceleration RMS. In the case, if the value of the controlled channel is higher than the set threshold level, the program will offer the operator to suspend the tests performance.

The program also has a fault detection system. In the case, if the system detects a malfunction, the program produces a message for the operator with description of the fault and recommendations in terms of troubleshooting.

The user can start or suspend the recording of the electrical signals from all active channels of the VCS controller using the “Recording” key

In the course of tests performance, it is possible to control the condition of the test specimen in real-time mode using the control channel. To enable this option, use the “Additional graphs” program.