Vibration Isolation

Introduction

This process is used to separate a particular system from its source of vibrations using isolators, which are the components that feature damping properties like springs, hydraulic and other materials with elastic attributes. This feature is generally used because high vibration levels can cause issues in the machines and cause noise issues to people as the vibrations travel in the form of noise through a structure of buildings, heavy machine slike pump, and AC compressor falls in this category including those of MRI setups and other electronic equipment used in medical facilities. 

Vibration isolation

This process is used to define the setup of a system that is effective in damping unwanted vibrations from a setup of a system, especially machinery that causes noise issues. Vibration isolation is further sub-categorized. 

• Rubber isolation: This form of isolation is conducted using rubber isolation pads which are also called rubber bearings. These are the most widely used form of vibration suppressor in the systems. This is the most advantageous apparatus in terms of durability as well. It possesses features that allow it to bear strong vertical capacity allowing mobility of horizontal displacement along with it, this form of isolation also provides support against excitations of earthquakes to a certain extent. Despite all these advantages this device possesses poor tension properties. At the current time, a multidimensional approach has been undertaken to mitigate this issue of normal rubber bearings.
• Sliding isolation: Sliding isolation is the process by which the vibrations are reduced using supportive components installed in between the base and the upper part of the machine. The advantage of this system lies in the fact that the isolation properties are triggered by the slightest of the ground motion and it does not allow it to resonate easily. It is essential to note that this setup is simple and is cost-effective. However, there are certain drawbacks with this setup, it has a poor restoring ability because it lacks lateral stiffness and the friction coefficient is unstable.
• Hybrid isolation: this form of isolation uses two or more sets of isolation procedures for an enhancement in the effectiveness of this process. This system of isolation utilized the advantages of different forms of isolation set-up mitigating the weaknesses. For example, when the rubber and sliding isolation set up is connected parallel, it provides an effective dampening attribute as associated with both the step-ups; the restoring capacity combined with the load-carrying attribute enhances the effectiveness.

Other than the setups various other isolation systems are used in the buildings for example, the inter-story isolation between the floor and pillars. Suspension isolation is used to reduce structure response in all directions.

The proportion of vibration energy transmission associated with vibration isolators is calculated by.

T= 1+2 ff  fn 2 1-ff2fn22+2ff2fn22

ff = forcing frequency of vibration (Hz)

fn = natural frequency of vibration isolator (Hz)

ξ = critical damping ratio 

Damping

Damping is a procedure used in the process of vibration isolation systems to reduce the force of vibration like oscillation, noise, and alternate electric currents near the resonance by dissipation of energy. The effect at resonance due to various methods of damping can be determined using ‘equivalent viscous damping’.

Vibration isolators with damping is calculated by, MA +CV+ Kz = f(t)

• A = acceleration, m/s2
• V = velocity, m/s
• D = displacement, m
• C = damping coefficient, Ns/m
• K = spring constant, N/m
• P = Peak vibration force, N
• f = frequency, Hz

Isolators

Vibration isolation can be achieved by various forms of isolators. There are materials with properties that exhibit high elasticity with damping properties. Hydraulics and elastomeric materials are most used as isolators, especially in the industrial sectors. Natural and butyl rubbers are some commonly used elastomers.

Conclusion

The usage of vibration isolation helps in the mounting of machines that have high vibration and noises and this method of approach thus allows enhancing the effectiveness of the products in use. The usage of materials with elastomeric properties called elastomers and apparatus is set up in such a way that reduces noise and protects from vibration waves as generated from the machine and the ground alike, like the earthquake waves.