GROUP #3

A vibration problem generally involves a source of vibration, a dynamical (or vibratory) system and the response.

It involves strategies and technologies implemented directly on the machinery or equipment generating vibrations to reduce or mitigate the vibrations generated.

Vibration Control at the Source

Lowering the machine's rotational speed without compromising its primary function.

Precision machining of rotors or crankshafts and selecting balanced configurations, like a 6-cylinder inline engine.

Decreasing flow speed by adjusting flow rate or cross-sectional area, using flow straighteners, or streamlining flow with guide vanes.

Helical spoilers can be added to chimneys to disrupt vortex shedding and minimize vibration. Perforated vertical plates near the wall can prevent shoshing in liquid reservoirs.

Prevented by ensuring proper lubrication through grease cups and regular inspections.

A rotating shaft with a keyway causing parametric excitation can be remedied by providing additional keyways at specific azmuthal locations.

Unbalanced forces and moments in reciprocating engine crankshafts and rotors require balancing techniques such as pivoted-carriage balancing machines and Gisholt-type balancing machines.

Portable sets are available for balancing single and two-plane rotors on-site.

Is a commonly used technique for reducing or suppressing unwanted vibrations in structures and machines.

Vibration Isolation

To achieve effective vibration isolation, the natural frequency of the system should be significantly lower than the forcing frequency, which is often equal to the rotational speed of the machine.

This can be accomplished by using soft springs and/or inertia blocks.

It is not only helps in achieving a low natural frequency but also limits the vibration levels of the machine.

Vibration of the machine and transmissibility near the resonance frequency can be controlled through damping.

Are mentioned as a solution that provides compliance (softness) as well as damping properties, making them useful for vibration isolation.

Are mechanical components commonly used for vibration isolation and damping in various industrial applications.

Bonded Rubber Springs

They are also effective in absorbing shocks and impacts, which can help protect sensitive equipment from damage.

This allows bonded rubber springs to provide both isolation and support.

This helps reduce the amplitude and duration of vibrations.

They can be designed to have specific stiffness and damping characteristics to match the requirements of a particular system.

They are relatively easy to install, making them a practical choice for retrofitting existing equipment.

Bonded rubber springs are used in a wide range of applications, including automotive suspension systems, industrial machinery mounts, building and structural isolation, and vibration control in aerospace and defense equipment.

Are designed to reduce vibrations by absorbing shock and providing support.

Is a system that replaces traditional metal springs with airbags.

Are devices used to reduce vibrations in structures and machines.

It has often been observed that the unbalanced forces transmitted to the foundation or support structure travel long distance through the structure as structure-borne sound and radiate sound.

It is effected by sudden change in characteristic impedance along the transmission path.

A liquid and a solid material

Serves as a form of impedance.

The compression of the wave at any point along the string can be described by a scalar quantity.

Are configurations of mechanical or material elements designed to dissipate sufficient vibrational energy to control vibrations or noise.

Is a mechanical engineering method for the absorption or minimization of vibrations.

Is the active application of force in an equal and opposite fashion to the forces imposed by external vibration.