Classical Mechanics: Part of A Series of Articles About
Classical Mechanics: Part of A Series of Articles About
Classical Mechanics: Part of A Series of Articles About
Classical mechanics
• History
• Timeline
Branches[show]
Fundamentals[show]
Formulations[show]
Core topics[hide]
• Damping (ratio)
• Displacement
• Equations of motion
• Fictitious force
• Friction
• Harmonic oscillator
• Motion (linear)
• Relative velocity
• Rigid body
o dynamics
o Euler's equations
• Vibration
Rotation[show]
Scientists[show]
• v
• t
• e
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The
word comes from Latin vibrationem ("shaking, brandishing"). The oscillations may be periodic, such
as the motion of a pendulum—or random, such as the movement of a tire on a gravel road.
Vibration can be desirable: for example, the motion of a tuning fork, the reed in a woodwind
instrument or harmonica, a mobile phone, or the cone of a loudspeaker.
In many cases, however, vibration is undesirable, wasting energy and creating unwanted sound. For
example, the vibrational motions of engines, electric motors, or any mechanical device in operation
are typically unwanted. Such vibrations could be caused by imbalances in the rotating parts,
uneven friction, or the meshing of gear teeth. Careful designs usually minimize unwanted vibrations.
The studies of sound and vibration are closely related. Sound, or pressure waves, are generated by
vibrating structures (e.g. vocal cords); these pressure waves can also induce the vibration of
structures (e.g. ear drum). Hence, attempts to reduce noise are often related to issues of vibration.
One of the possible modes of vibration of a circular drum (see other modes).
Car Suspension: designing vibration control is undertaken as part
of acoustic, automotive or mechanicalengineering.
Contents
• 1Types of vibration
• 2Vibration testing
• 3Vibration analysis
o 4.1Eigenvalue problem
o 4.4Rigid-body mode
• 5See also
• 6References
• 7Further reading
• 8External links
Types of vibration[edit]
Free vibration occurs when a mechanical system is set in motion with an initial input and allowed to
vibrate freely. Examples of this type of vibration are pulling a child back on a swing and letting it go,
or hitting a tuning fork and letting it ring. The mechanical system vibrates at one or more of
its natural frequencies and dampsdown to motionlessness.
Damped vibration: When the energy of a vibrating system is gradually dissipated by friction and
other resistances, the vibrations are said to be damped. The vibrations gradually reduce or change in
frequency or intensity or cease and the system rests in its equilibrium position. An example of this
type of vibration is the vehicular suspension dampened by the shock absorber.