Units of Vibration – Examples, Definition, Units, Conversion Chart

Vibration, a physical phenomenon that involves oscillations around an equilibrium point, is quantified in various units depending on the context and the properties being measured.

What are Units of Vibration?

SI Unit of Vibration

The hertz (Hz) is the SI unit for measuring the frequency of vibrations. It quantifies the number of cycles a vibrating object completes in one second. Commonly used across various scientific and engineering disciplines, this unit plays a crucial role in analyzing and controlling vibrations.

Types of Vibration

Vibration, a dynamic phenomenon that occurs in various forms, can be broadly classified into several types based on how the motion is transmitted and experienced. Understanding these types helps professionals in fields such as engineering and acoustics to design better systems and mitigate unwanted vibrations.

Free Vibration

Occurs when an object or system vibrates naturally without any external force after being initially disturbed. It continues until the energy dissipates due to damping mechanisms inherent in the system. This type of vibration is critical in understanding the natural frequencies of structures and mechanical components.

Forced Vibration

Happens when a time-varying external force is applied to a system. The resulting vibration matches the frequency of the force, not the natural frequency of the object. This knowledge is essential for designing systems that can withstand repetitive external forces, such as in automotive and aerospace applications.

Damped Vibration

In this type, the vibrations gradually decrease over time due to the presence of a damping force, which dissipates the system’s energy. Damped vibrations are particularly significant in designing buildings and vehicles that need to absorb shocks efficiently and minimize oscillation amplitudes.

Random Vibration

Characterized by vibrations that occur at unpredictable frequencies and amplitudes. This type is commonly analyzed in environments with complex disturbances such as earthquakes or rough terrain driving. Understanding random vibrations helps in improving the reliability and durability of structures and equipment exposed to these conditions.

List of Vibration Units

Hertz (Hz)

The Hertz is the SI unit of frequency, named after Heinrich Hertz. It measures the number of cycles per second that a vibrating object completes. It is universally used in physics and engineering to quantify vibrational and oscillatory frequencies.

Meter per Second Squared (m/s²)

This unit is widely used in engineering applications, particularly for measuring the acceleration due to vibrations. It represents the rate of change of velocity per second.

Gal (Gal)

The Gal, named after Galileo, is a unit of acceleration commonly used in seismology to measure earthquake vibrations and other ground movements.

Decibel (dB)

Decibels measure the relative loudness of sounds as perceived by the human ear. In vibration analysis, it is used to quantify the intensity level of the vibration.

Cycles per Second (cps)

Cycles per second is an older term equivalent to Hertz, indicating the frequency of cycles a vibrating object completes in one second. It was more commonly used before the adoption of the Hertz in scientific contexts.

Conversion of Vibration Units

Hertz to Cycles per Second

• Conversion: 1 Hz = 1 cps
• Example: To convert 50 hertz to cycles per second:
• 50 Hz = 50 cps

Meter per Second Squared to Gal

• Conversion: 1 m/s² = 100 Gal
• Example: To convert 9.8 meters per second squared to Gals:
• 9.8 m/s² × 100 = 980 Gal

Gal to Meter per Second Squared

• Conversion: 1 Gal = 0.01 m/s²
• Example: To convert 500 Gals to meters per second squared:
• 500 Gal × 0.01 = 5 m/s²

Decibel to Hertz (Relative Conversion)

• Conversion: Conversion varies based on reference levels and context.
• Example: Not directly convertible without additional context about the signal or noise level.

Hertz to Decibel (Relative Conversion)

• Conversion: Conversion varies, often requires intensity or power level.
• Example: Not directly convertible without knowing the intensity level and reference value.

Cycles per Second to Hertz

• Conversion: 1 cps = 1 Hz
• Example: To convert 60 cycles per second to hertz:
• 60 cps = 60 Hz

FAQ’S

What is vibration measured by?

Vibration is measured by sensors like accelerometers and seismometers, which quantify motion in units such as hertz (Hz) or meters per second squared (m/s²).

What is dB in vibration?

In vibration, dB (decibels) quantifies the intensity relative to a reference value, commonly used to measure sound and vibration levels.

What is vibration value?

Vibration value refers to the magnitude of vibration, typically expressed in terms of amplitude, frequency, and acceleration, depending on the measurement context.