Torsional Vibration Analysis Using Rotational Laser Vibrometers.

Area of Science:

• Rotor dynamics and mechanical vibrations.
• Non-invasive measurement techniques.
• Finite element analysis in mechanical engineering.

Background:

• Torsional vibration is a critical failure source in rotating machinery, difficult to measure non-invasively.
• Traditional torsional vibrometers are invasive, complex, and impractical for field use.
• Laser torsional vibrometers offer a reliable, non-invasive, and portable alternative.

Purpose of the Study:

• To develop and validate a reliable procedure for measuring torsional vibrations using two laser vibrometers.
• To establish a method for relative calibration of different laser vibrometer heads.
• To compare experimental results with numerical simulations for validation.

Main Methods:

• Utilized two laser heads with distinct measurement capabilities on an experimental test rig.
• Performed relative calibration between the two laser vibrometers.
• Compared experimental torsional vibration measurements with a 1D finite element model.

Main Results:

• Successfully defined a reliable measuring procedure for detecting torsional mode-shapes and natural frequencies.
• Detailed the relative calibration process, crucial for correlating signals from different machine sections.
• Achieved good agreement between experimental measurements and numerical simulation results.

Conclusions:

• The developed procedure effectively utilizes two laser torsional vibrometers for accurate torsional vibration analysis.
• Relative calibration is essential for correlating measurements across different sections of a machine.
• The findings support the use of laser torsional vibrometers for diagnosing issues in real-world rotating machinery.