Vibration analysis is one of the most powerful and widely used predictive maintenance techniques. It involves measuring and analyzing the vibration patterns of rotating machinery to detect developing faults before they lead to catastrophic failures.
Every rotating machine produces a unique vibration signature based on its design, operating conditions, and mechanical condition. By understanding these signatures, reliability engineers can identify specific fault conditions.
Different mechanical faults produce vibrations at characteristic frequencies:
Produces vibration at 1X running speed (fundamental frequency). This is one of the most common faults in rotating machinery and typically shows high radial vibration.
Angular misalignment produces 1X and 2X running speed vibrations, while parallel misalignment primarily produces 2X vibrations with high axial components.
Rolling element bearings produce vibrations at specific frequencies based on bearing geometry:
Gear mesh frequency and its harmonics indicate gear condition. Sidebands around gear mesh frequency can indicate specific gear problems.
Successful vibration analysis depends on proper data collection:
Establish consistent measurement points on each machine. Typically measure in three directions: horizontal, vertical, and axial at bearing locations.
Provides information about the time-based characteristics of vibration signals. Useful for identifying impacting, modulation, and transient events.
Converts time-based signals to frequency domain using Fast Fourier Transform (FFT). This is the primary tool for fault identification.
Particularly useful for bearing fault detection. Demodulates high-frequency signals to reveal low-frequency modulation patterns.
Vibration severity is typically assessed using standards such as:
Choose appropriate vibration analyzers and sensors based on your specific needs and budget. Consider factors like frequency range, dynamic range, and portability.
Invest in proper training for your team. ISO 18436 provides a framework for vibration analyst certification at multiple levels.
Establish a robust database system for storing and trending vibration data. This historical data is crucial for identifying developing problems.
As your program matures, consider implementing advanced techniques such as:
Vibration analysis is a powerful tool for maintaining machinery reliability. Success requires proper equipment, training, procedures, and commitment to continuous improvement. When implemented correctly, vibration analysis can significantly reduce maintenance costs and improve equipment reliability.