Vibration

Types of Vibration

• Free vibration occurs when a system is set in motion and allowed to vibrate freely
• Forced vibration happens when a time-varying disturbance is applied to a system
• Damped vibration occurs when the energy of a vibrating system is gradually dissipated
• Harmonic disturbance is a periodic and steady-state input that can cause forced vibration
• Non-harmonic disturbance is a non-periodic input that can also cause forced vibration

Vibration Isolation

• Vibration isolation prevents the transmission of vibration from one component to others
• Vibrations propagate via mechanical waves, and certain linkages conduct vibrations more efficiently
• Passive vibration isolation uses materials and linkages to absorb and damp mechanical waves
• Active vibration isolation involves sensors and actuators that produce disruptive interference
• Vibration isolation is important in engineered systems and habitable spaces

Vibration Testing

• Vibration testing introduces a forcing function into a structure to examine its response
• Shakers are commonly used to apply the forcing function to the structure
• Vibration testing can assess the ability of a device to function in a vibration environment
• Different types of vibration testing include sine tests and random tests
• Vibration testing can be conducted in multiple axes simultaneously

Vibration Analysis

• Vibration analysis aims to reduce maintenance costs and equipment downtime
• It is used in a condition monitoring program to detect equipment faults
• Vibration analysis is commonly used to detect faults in rotating equipment
• Common faults detected include imbalance, misalignment, and bearing faults
• Vibration analysis can be displayed as time waveforms or spectra

Related Studies and Concepts

• The studies of sound and vibration are closely related and fall under acoustics
• Sound is generated by vibrating structures and can induce vibration in other structures
• Attempts to reduce noise are often related to issues of vibration
• Designing vibration control is undertaken in acoustic, automotive, and mechanical engineering
• Machining vibrations are common in the process of subtractive manufacturing
• Frequency response function (FRF) is the transfer function of the system in vibration analysis
• FRF has both magnitude and phase components and can be used to determine vibration characteristics

Vibration Data Sources