Human comfort

1. Vibration control
R.Narasimha Swamy
Senior consultant
narasimhaswamy@yahoo.com

2. 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.

3. Understanding
the cause and
proper choice
of Isolator is
necessary
for optimum
performance

5. 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.

6. Classical methods and measures
to control vibration

7. SDOF: Single degree of freedom

8. 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.

9. ISOLATION

10. Case study of vibration control

11. 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.

12. 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.

13. 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.

20. Floating floor for studios

22. A short video on noise by Ted Talk

23. Thank you