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Vibration control in mechanical systems• The first level of methods attempts to reduce the
excitation responsible for the vibration at the source.
• The system parameters namely inertia, stiffness and damping are to be optimally chosen or modified to reduce the response to a given excitation.
• The balancing of inertial forces, smoothening of fluid flows and proper lubrication at joints are effective methods and should be considered whenever possible.
• Transmission of path of vibration needs to be worked on for effective isolation.
• Objective diagnostic tests and analysis can pinpoint the problem areas.
Understanding the cause and proper choice of Isolator is necessary for optimum performance
Analytical methods• For diagnosing and identifying the cause of
vibration.
• Provides useful data on important parameter viz displacement/velocity/acceleration which can be transformed to frequency domain for in depth interpretation.
• Helps in specifying and choosing right device and measures to combat and reduce vibration.
• Can be used for validating the solution so chosen.
Classical methods and measures to control vibration
SDOF: Single degree of freedom
Tuned absorbers• Useful for reducing vibration levels in those systems in
which an excitation frequency is close to or coincides with a natural frequency of the system
• The principles of un-damped and damped tuned absorbers can be understood by outlining first the analysis of the damped absorber
• Un-damped absorber as a special case.
ISOLATION
Case study of vibration control
Floating floor• Floating floor is fast becoming inevitable due to
problems associated with structure borne noise in Studios and sensitive installation housed in multi storey building.
• A floating floor system is composed of two mass layers separated by an airspace and decoupled from one another with resilient mountings.
• This design principle will, with proper flanking noise control, provide much greater values of sound insulation than can be achieved with single solid floor slabs.
• The result is a high performance acoustic floor at a relatively low weight that can be tolerated by modern building structures.
Applications of floating floor• Used in sound studios are constructions with slabs of
concrete to keep the resonance frequency down.
• The manufacture of semi conductor devices use massive floating floors with hundreds of tons in weight of concrete to avoid vibration affecting mask alignment.
• They are one of the requirements for the THX Hi-Fi sound reproduction standard for movie theatres, screening rooms, home theatres and car audio systems.
• Employed in Auditoria, Casinos/nightclubs, Bowling alleys, Sports halls, Audiology suites, Gymnasiums , residential or corporate premises, Music practice rooms, Health & Fitness suites, Plant and machinery rooms.
Types• Panel Mount Systems
– These are the standard type of floating floors that incorporate neoprene, glass fibre or spring isolators which provide an acoustic break and a fixed air gap between the ‘floating’ concrete floor and the structural building slabs.
• Jack-up Systems– These have a similar construction to the Panel Mount
System with the addition of adjustable isolators providing the ability to vary the air gap between the ‘floating’ concrete floor slab and the structural building slab.
• Acoustic Panel Systems– These systems incorporate modular acoustic panels in-lieu
of the concrete floor slab. Using pre-fabricated modular panels avoids wet trades on site and enables the floor to be dismantled and re-located if required.
Floating floor for studios
A short video on noise by Ted Talk
Thank you
